Multi-mode power-efficient light and gesture sensing in image sensors

ABSTRACT

Various embodiments comprise apparatuses and methods including an image sensor. In one example, the image sensor includes a read-out integrated circuit, a plurality of pixel electrodes, an optically sensitive layer, and a top electrical contact. In a first low-power mode, electrical current passing through the top electrical contact is configured to be sensed, and independent currents passing through the plurality of pixel electrodes are configured not to be sensed independently. In a second high-resolution mode, independent currents passing through the plurality of pixel electrodes are configured to be sensed independently. Additional methods and apparatuses are described.

PRIORITY CLAIM

The present application claims the benefit of priority of U.S.Provisional Patent Application Ser. No. 62/031,414, filed Jul. 31, 2014,entitled “MULTI-MODE POWER-EFFICIENT LIGHT AND GESTURE SENSING IN IMAGESENSORS,” and further claims the benefit of priority, as acontinuation-in- art patent application, to U.S. patent application Ser.No. 14/732,314, entitled “SENSORS AND SYSTEMS FOR THE CAPTURE OF SCENESAND EVENTS IN SPACE AND TIME,” filed Jun. 5, 2015, both of which areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The present application relates generally to the field of optical andelectronic systems and methods, and methods of making and using thedevices and systems.

BACKGROUND

Mobile devices are widely employed for communications, computing, andsocial media. They include camera systems—often at least two, arear-facing and front-facing—for the capture of images. These camerasystems can also be regarded as input devices for the communicationbetween the user of the mobile device, and the mobile device's softwareand systems. One means of communication these camera systems can enableis recognition of gestures in space and time implemented by the user ofthe mobile device.

The consumption of electrical power by mobile devices is an object ofcontinued focus, with the goal being to minimize power and, for a givenbattery, extend the operating lifetime of the device between requiredcharges. Minimizing the consumption of electrical power in electronicproducts is of critical and ever-growing importance. As one example of ameans of minimizing power, it is possible to regulate the brightness ofa display on a mobile device in order to use only the necessary power.Mobile devices often employ sensors that provide dimming of the displaybrightness in view of sensed information regarding the level of ambientlighting. Moreover some devices use multiple sensors and differentwavelengths to enable functions such as proximity sensing and basicgesture recognition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 2A, 2B, and 4 through 6 show embodiments of an imagesensor array on which images are projected and registered, withadditional sensing regions being shown, within an image circle of alens;

FIGS. 3A and 3B show a top view and a side view, respectively ofcurrent-collecting electrode set intended for use in a peripheral regionof a chip;

FIG. 3C shows a current monitor circuit that may be connected to thecurrent collected through at least one of the electrodes of FIGS. 3A and3B;

FIG. 7 shows overall structure and areas related to a quantum dot pixelchip, according to an embodiment;

FIG. 8 shows an example of a quantum dot;

FIG. 9 shows a two-row by three-column sub-region within a generallylarger array of top-surface electrodes;

FIG. 10 illustrates a 3T transistor configuration for interfacing withthe quantum dot material;

FIG. 11 is a block diagram of an example system configuration that maybe used in combination with embodiments described herein;

FIG. 12 shows an embodiment of a single-plane computing device that maybe used in computing, communication, gaming, interfacing, and so on;

FIG. 13 shows an embodiment of a double-plane computing device that maybe used in computing, communication, gaming, interfacing, and so on;

FIG. 14 shows an embodiment of a camera module that may be used with thecomputing devices of FIG. 12 or FIG. 13;

FIG. 15 shows an embodiment of a light sensor that may be used with thecomputing devices of FIG. 12 or FIG. 13;

FIG. 16 and FIG. 17 show embodiments of methods of gesture recognition;

FIG. 18 shows an embodiment of a three-electrode differential-layoutsystem to reduce external interferences with light sensing operations;

FIG. 19 shows an embodiment of a three-electrode twisted-pair layoutsystem to reduce common-mode noise from external interferences in lightsensing operations;

FIG. 20 is an embodiment of time-modulated biasing a signal applied toelectrodes to reduce external noise that is not at the modulationfrequency;

FIG. 21 shows an embodiment of a transmittance spectrum of a filter thatmay be used in various imaging applications;

FIG. 22 shows an example schematic diagram of a circuit that may beemployed within each pixel to reduce noise power;

FIG. 23 shows an example schematic diagram of a circuit of aphotoGate/pinned-diode storage that may be implemented in silicon;

FIG. 24 shows a top-view schematic of an image sensor in which aphotosensitive material, also known as an optically sensitive layer, isprovided on top of an integrated circuit, such as a CMOS integratedcircuit;

FIG. 25 shows a top-view schematic of an image sensor that is analogousto FIG. 1; except that, distinct from FIG. 24, there are now defined (inthis example embodiment) four separate regions of top transparentelectrical contact;

FIG. 26 shows the concept of FIG. 25 further extended to dividing theVfilm top contact in n*m areas for higher spatial resolutions;

FIG. 27 shows regions of difference sizes, areas, and shapes that can beprovided by using distinct shapes;

FIG. 28 shows an example means for resetting pixel electrodes;

FIG. 29 shows signals that may be related to an external controlleremployed to power up a readout chip in order to enable still or videocapture; and

FIG. 30 shows an open loop system where a controller decides when topower up the readout chip, the device display, or other functions as afunction of the signal provided by the current sensing circuit.

DETAILED DESCRIPTION

Various embodiments described herein provide a means of utilizing acamera system as an image-capture device, and also asgesture-recognition device, while minimizing power consumption.

In example embodiments, the imaging array region operates at power onlywhen being used in image capture commensurate with its resolution.During periods of time when gesture recognition, or proximity detection,is desired, power is minimized by providing power only to sensingregions.

In embodiments, the sensing regions reside on the same integratedcircuit as the imaging array.

In embodiments, the sensing regions are read using circuitry on the sameintegrated circuit, but providing for much lower power operation than ifthe image array region circuitry were being employed.

In embodiments, the sensing regions are read using circuitry providedoff-chip. In such embodiments, the sensing regions could be termedpassive: they consist of, for example, light-absorbing materials, cladby electrical contacts, where electrically conductive materials providefor the conveyance of electrical signals for subsequent readout usingseparate low-power circuits.

Depicted in FIG. 1A is an embodiment of the disclosed subject matter.Region 1 is the image sensor array on which images are projected andregistered. Regions 2, 3, 4, 5 are additional sensing regions. Region 6depicts the image circle, i.e., region 6 represents the projection ofthe focusing lens system onto the plane of the image sensor. Labels areanalogous in FIG. 1B.

As depicted in FIGS. 1A and 1B, the additional sensing regions 2, 3, 4,5 have been placed such that they lie outside of rectangular imagesensor region 1; yet lie within the image circle 6.

As a result, Regions 2, 3, 4, 5 will be exposed to illumination that issimilarly in-focus as the illumination onto Region 1.

In embodiments, Regions 2, 3, 4, 5 may be employed as light sensors. Inembodiments, Regions 2, 3, 4, 5 may be connected to on-chip electroniccircuitry that provides for the digitization of levels proportional withthe illumination over a period of time. In embodiments, these levels maybe reported as a digital number DN.

In alternate embodiments, Regions 2, 3, 4, 5 collect photocurrent intoon-chip charge stores that may be read using off-chip electronics.

In further alternate embodiments, Regions 2, 3, 4, 5 collectphotocurrent that is carried off-chip for reading using off-chipcircuitry.

In embodiments, light sensing using at least one of Regions 2, 3, 4, 5can be provided while little or no electrical power is drawn by Region1. As a result, a low-power operating mode may be provided wherein thelight projected from a scene is registered using the Regions 2, 3, 4, 5.

In an embodiment, an illumination source may be employed to illuminate ascene; and Regions 2, 3, 4, 5 may be read for their DN, charge, orphotocurrent levels to register light returning from the illuminatedscene.

In various embodiments, IR sub arrays could be the same or largerpixels, and may use true GS Positioned in both examples to have anincreased or maximum parallax error from its opposite. FIG. 1B showsplacement if there is chip area there and it is efficient to have itthat far out. In embodiments, all four IR sub arrays may have their ownpowering scheme so that when they are on it does not use full power ofmain array. In embodiments, a third tier of lower power in binned modemay be used so that these sub arrays could be used as massive pixels forproximity detection applications.

Referring to FIGS. 2A and 2B, cameras may employ a spectrally-selectivefilter, such as one that passes visible light to the visible-circle 6. Aring around the outside of circle 6, defined as outer shell 7, maycontinue to receive appreciable infrared light. In embodiments, sensingRegions 2, 3, 4, 5 may be placed within outer shell 7 such that theyreceive infrared illumination; whereas the majority of imaging array 1may be elected to lie within the visible-receiving inner circle 6.

In embodiments, multiple, independently-powered light sensing regionsare illuminated using a single optic. For example, the image sensorarray represents a first independently-powered light sensing region. Theat least one peripheral light sensors consume an electrical power thatis substantially independent of the electrical power of the image sensorarray.

In embodiments, a specialized IR filter could be employed where itsefficiency of filtering IR can drop off as incident angles increase,allowing the IR sub arrays to receive more IR photons, while keeping thevisible main array 1 shielded from IR. Some of the visible sensor'scorners may be exposed to IR, but could be image processed out,especially since corner artifacts are expected anyways (such as lensshading). In the FIG. 2B, a stronger IR filter circle gets to be biggercovering more of the corners of the visible main array 1.

In various embodiments, IR sub arrays could be the same or largerpixels, and may use true GS Positioned in both examples to have anincreased or maximum parallax error from its opposite. FIG. 2B showsplacement if there is chip area there and it is efficient to have itthat far out. In embodiments, all four IR sub arrays may have their ownpowering scheme so that when they are on it does not use full power ofmain array. In embodiments, a third tier of lower power in binned modemay be used so that these sub arrays could be used as massive pixels forproximity detection applications.

In an embodiment, an infrared illumination source may be employed toilluminate a scene. Imaging array region 1 will principally registervisible light; and Regions 2, 3, 4, 5 will receive the sum of visibleand infrared light, and may be read for their DN, charge, orphotocurrent levels to register light returning from the illuminatedscene. In embodiments, the image sensor circuit may include alignmentmarks that define a spatial relationship to the sensing array 1,facilitating alignment of the infrared-blocking element placement duringmodule assembly.

In embodiments, the infrared filter may be provided that substantiallyoverlies the array region 1, and offers a substantially rectangularshape similar to, and aligned with, region 1. In this embodiment, theregions outside the rectangular array region are provided with infraredlight, whereas the rectangular array region receives principally visiblelight for imaging. In embodiments, a filter is provided thatsubstantially removes infrared light from the image sensor plane over atleast the dimensions of the image sensor array rectangle; and thatallows infrared light to reach the image sensor surface in at least oneof the peripheral image sensing regions.

In embodiments, the optical system used to collect and focus light ontothe imaging array 1 may have a first field of view, such as for example120°; yet it may be desired that the image sensors register light from asmaller field of view. In this embodiment, angularly-selective elementsmay be added on top of the sensing regions 2, 3, 4, 5. An exampleincludes an aperture that protrudes vertically from the surface of theintegrated circuit; and that ensures that light is collected only over adefined field of view. In embodiments, the image sensor circuit mayinclude alignment marks that define a spatial relationship to thesensing regions 2, 3, 4, 5; facilitating alignment of theangularly-select element placement during module assembly.

In embodiments, image array regions and light sensing regions such asthose may be accomplished by: Forming an integrated circuit;monolithically integrating an optically sensitive layer atop theintegrated circuit to provide light sensing in the image array regionsand the light sensing regions.

In embodiments, image array regions and light sensing regions such asthose may be accomplished by: Forming an integrated circuit;monolithically integrating an optically sensitive layer atop theintegrated circuit, and patterning it such that the originally-formedintegrated circuit is no longer covered by the light-sensing layer, andits light sensing is provided by the originally-formed integratedcircuit; while leaving the optically-sensitive material in the lightsensing regions to provide light sensing.

In embodiments, image array regions and light sensing regions such asthose may be accomplished by: Forming an integrated circuit;heterogeneously integrating light sensing materials or devices atopregions of the integrated circuit; where the light sensing materials ordevices do not substantially disrupt image formation on the image arrayregion; and where they provide additional light sensing capabilitiessuch as those described herein.

In embodiments, a single class of monolithically-integrated opticallysensitive layer may overlie portions of the integrated circuit. Inregions of the integrated circuit where the optically sensitive layeroverlies a pixelated region of pixel electrodes, the optically sensitivelayer may function as the light absorber associated with numerous pixelregions, and the array of pixelated regions taken together with theoptically sensitive layer may constitute an image sensor region portionof the integrated circuit. In regions of the integrated circuit wherethe optically sensitive layer overlies at least one large-areaelectrode, the large-area electrode combined with the opticallysensitive layer may constitute a passive light sensor. In embodimentsthe passive light sensor may be used in a first low-power mode to sensea state or a gesture. In embodiments the image sensor portion of theintegrated circuit may be employed in a second imaging mode in which theimage sensor circuit portion is biased and operating, typicallyconsuming at least 100 times more power than when operating in the firstmode. An example embodiment is show in FIG. 1B, where the opticallysensitive material overlying the main visible light image sensor (region1 in FIG. 1B) is substantially of the same composition as the opticallysensitive material overlying the peripheral sensing regions (2, 3, 4,5). An example embodiment is show in FIG. 2A, where the opticallysensitive material overlying the main visible light image sensor (region1 in FIG. 2A) is substantially of the same composition as the opticallysensitive material overlying the peripheral sensing regions (2, 3, 4,5).

In embodiments, two distinct classes of monolithically-integratedoptically sensitive layer may overlie portions of the integratedcircuit. In regions of the integrated circuit where an opticallysensitive layer overlies a pixelated region of pixel electrodes, theoptically sensitive layer may function as the light absorber associatedwith numerous pixel regions, and the array of pixelated regions takentogether with the optically sensitive layer may constitute an imagesensor region portion of the integrated circuit. In an exampleembodiments in which the image sensor array is required to acquirevisible-spectrum images, the optically sensitive layer overlying theimage sensor region may be designed to sense visible light with highsensitivity. For example, the optically sensitive material in this imagesensor array region may be a strong absorber of visible wavelengths oflight in the range 480 nm to 630 nm, but it may be substantiallytransmissive to light (nonabsorbing of light) in for example the nearinfrared (NIR) region beyond 830 nm. In regions of the integratedcircuit where an optically sensitive layer overlies at least onelarge-area electrode, the large-area electrode combined with theoptically sensitive layer may constitute a passive light sensor. In anexample embodiment in which the peripheral sensors are required toacquire infrared-spectrum light intensity related information, theoptically sensitive layer overlying the peripheral regions may bedesigned to sense infrared light with high sensitivity. For example, theoptically sensitive material in this peripheral sensor region may be astrong absorber of near infrared light in the spectral range 800 nm to850 nm. In another embodiment, the optically sensitive material in thisperipheral sensor region may be a strong absorber of near infrared lightin the spectral range 900 nm to 950 nm. In embodiments the passive lightsensor may be used in a first low-power mode to sense a state or agesture. In embodiments the image sensor portion of the integratedcircuit may be employed in a second imaging mode in which the imagesensor circuit portion is biased and operating, typically consuming atleast 100 times more power than when operating in the first mode. Anexample embodiment is show in FIG. 1B, where the optically sensitivematerial overlying the main visible light image sensor (region 1 in FIG.1B) is of a first composition wherein it is principally a strong visiblelight absorber; and the optically sensitive material overlying theperipheral sensing regions (2, 3, 4, 5) is of a second compositionwherein it is a strong NIR absorber. An example embodiment is show inFIG. 2A, where the optically sensitive material overlying the mainvisible light image sensor (region 1 in FIG. 2A) is of a firstcomposition wherein it is principally a strong visible light absorber;and the optically sensitive material overlying the peripheral sensingregions (2, 3, 4, 5) is of a second composition where it is a strong NIRabsorber.

In prior art, an image sensor array region is chiefly responsible forlight absorption and light sensing; and an outer peripheral area beyondthe typically rectangular image array is not utilized for light sensing,but instead is primarily employed in electronics. In cases theperipheral-to-the-rectangular-array region may be shielded from lightimpinging upon optically sensitive material using a light-obscuringmaterial such as a metal or other substantially opaque material.

In embodiments of the disclosed subject matter, the region peripheral tothe typically-rectangular image array region may be employed in lightsensing. Optically sensitive material in the peripheral region may bedisposed for highly efficient light absorption, as opposed to beingobscured using substantially opaque material. In embodiments, theperipheral region may contain both analog, mixed-signal (such as ananalog-to-digital converter), and/or digital electronic circuitry; andmay also include optically sensitive material for light sensing. Inembodiments, in the peripheral region, an optically sensitive layer mayoverlie electronic circuitry, and at least a portion of the electroniccircuitry in the peripheral region may perform functions that are notdirectly related to the performance of the light sensing functionimplemented by the overlying optically sensitive material. For example,a portion of the electronic circuitry may be devoted to managing andprocessing signals and digital information related to the image sensorarray; while at least a portion of the optically sensitive materialoverlying the electronic circuitry may be devoted to sensing light fromthe peripheral (as distinct from the imaging array) region.

Referring now to FIG. 3A that shows a top view of an embodiment of thedisclosed subject matter. In FIG. 3A, a current-collecting electrode setintended for use in a peripheral region of the chip is depicted.Features 301 present electrodes that collect photocharge from theoptically sensitive layer. Features 303 are regions of dielectric.Referring to FIG. 3B, a side view of a cross-section through a row ofelectrodes 301 is provided. The electrodes are again denoted 301 and adielectric such as, for example, SiO₂ or Si₃N₄ is labeled 303. Vias arelabeled 302 and these provide conduction of current from the opticallysensitive material 305 down to a common contact 304. Layer 304 may forexample be Metal5 (M5) in a typical interconnect stack, and the metalelectrodes may be formed using Metal6 (M6) of a typical interconnectstack. The label 306 represents the remaining interlayer dielectricbetween the substrate 307 (e.g., a silicon substrate) and thecurrent-collecting system described by 301, 302, 303, 304. A topsubstantially transparent contact 308 may be used to provide for anelectrical bias across the optically sensitive layer 305.

In embodiments, photoelectrons generated in the optically sensitivelayer 305 are collected by the electrodes 301 while photoholes arecollected by common top electrode 308. The currents flowing through themultiple electrodes 301 and vias 302 are aggregated in the commoncontact 304. The current may be monitored using a current-monitoringcircuit that is connected to 304 and/or to 308, for these two contactswill collect photocurrents of similar amplitudes. The photocurrent isrelated to the rate of absorption of photons in the region of opticallysensitive layer 305 that overlies the set of electrodes 301 (shown bothin the top view of FIG. 3A and the side view of FIG. 3B). The effectivearea of the light sensor is defined approximately by the largerrectangle 309 of FIG. 3A that encompasses the set of electrodes 301.Although a 3×4 array of electrodes is shown, a person of ordinary skillin the art will recognize that more or fewer electrodes may be employed.

Referring again to FIG. 3B, a current is provided from at least one ofthe electrode 308 or the electrode 304 and that this current can bemonitored. During this current-monitoring procedure, if imageacquisition is not required by the central image sensor array, theintegrated circuit may be powered down. In this example, an electricalbias between 304 and 308 can be provided by off-chip circuitry, such asa voltage supply elsewhere in a module or in a device (such as, forexample, in a smartphone). Alternatively, during this current-monitoringprocedure, if image acquisition is not required by the central imagesensor array, the integrated circuit may supply an electrical biasbetween 304 and 308, and the chip can thus operate in an extremelow-power mode: for example, if full-speed image sensor readout moderequired 250 of power, the extreme low-power mode could be a 1 mW powermode.

In embodiments in which electrons are to be collected using 304,electrode 304 can be positioned at, for example, +2 V, and electrode 308can be positioned at, for example, −1 V. Ranges are possible, such aselectrode 304 may be biased in the range of 1 V to 3 V, and electrode308 may be biased in the range of −3 V to −1 V. Entirely positive biasranges are possible, such as electrode 308 biased to ground, forexample, 0 V, and electrode 304 biased to voltages in the range of, forexample, +2 V to +4 V.

In embodiments in which electrons are to be collected using theelectrode 308, the electrode 308 can be positioned at +2 V, and theelectrode 304 can be positioned at −1 V. Ranges are possible, such asthe electrode 308 being biased in the range of, for example, 1 V to 3 V,and the electrode 304 being biased in the range of, for example, −3 V to−1 V. Entirely positive bias ranges are possible, such as the electrode304 being biased to ground, for example, 0 V, and the electrode 308being biased to voltages in the range of, for example, +2 V to +4 V.

Referring now to FIG. 3C, the current through the electrode 308 and theelectrode 304 can be monitored using a circuit. The current isproportional to the incident intensity of illumination of the lightsensing region 309 of FIG. 3A.

With continuing reference to FIG. 3C, a current monitor 311 may beconnected to the current collected through at least one of theelectrodes 308 and 304. In embodiments, a charge pump may be used toprovide a voltage (such as 3 V typically, with a range of, for example,2 V to 4 V) to the electrode 304 while the electrode 308 is held at ornear ground (typically 0 V). Using a clock, a capacitor, and a diode,the charge pump clock may be used to provide an estimate of thetime-averaged current passing through the monitored node. The resultantcounter value can be updated with a periodicity, such as at periodicintervals such as 1 millisecond intervals. In embodiments, the countermay be polled by a processor (such as a processor of a smartphone). Ifthe value exceeds a threshold, this triggers an event seen by theprocessor, and the processor can be programmed to implement an action.For example, the processor can convey a “wake-up” event to a portion ofthe system (e.g., the smartphone).

FIGS. 4 through 6 show additional embodiments of an image sensor arrayon which images are projected and registered, with additional sensingregions being shown, within an image circle of a lens. In the embodimentof FIG. 4, the four single pixel light and proximity IR sensors areQuantum Film layered on top of areas of the image sensor that areoptically inactive and could operate independently or be combined/binnedin analog to 1 pixel. They could also be used in passive mode, therebyreducing overall power consumption. In various embodiments, IR subarrays could be the same or larger pixels, and may use true GSPositioned in both examples to have an increased or maximum parallaxerror from its opposite. FIG. 1B shows placement if there is chip areathere and it is efficient to have it that far out. In embodiments, allfour IR sub arrays may have their own powering scheme so that when theyare on it does not use full power of main array. In embodiments, a thirdtier of lower power in binned mode may be used so that these sub arrayscould be used as massive pixels for proximity detection applications.

In the embodiment of FIG. 5, the four single pixel light and proximityIR sensors are Quantum Film layered on top of areas of the image sensorthat are optically inactive and could operate independently or becombined/binned in analog to 1 pixel. They could also be used in passivemode, thereby reducing overall power consumption. In variousembodiments, a standard IR filter may be placed just on the main imagesensor. Alignment can be achieved by, for example, providing alignmentmarks or mechanical anchors. In various embodiments, IR sub arrays couldbe the same or larger pixels, and may use true GS Positioned in bothexamples to have an increased or maximum parallax error from itsopposite. FIG. 1B shows placement if there is chip area there and it isefficient to have it that far out. In embodiments, all four IR subarrays may have their own powering scheme so that when they are on itdoes not use full power of main array. In embodiments, a third tier oflower power in binned mode may be used so that these sub arrays could beused as massive pixels for proximity detection applications.

In the embodiment of FIG. 6, the four single pixel light and proximityIR sensors are Quantum Film layered on top of areas of the image sensorthat are optically inactive and could operate independently or becombined/binned in analog to 1 pixel. They could also be used in passivemode, thereby reducing overall power consumption. In variousembodiments, a standard IR filter may be placed just on the main imagesensor. Alignment can be achieved by, for example, providing alignmentmarks or mechanical anchors. In various embodiments, IR sub arrays couldbe the same or larger pixels, and may use true GS Positioned in bothexamples to have an increased or maximum parallax error from itsopposite. FIG. 1B shows placement if there is chip area there and it isefficient to have it that far out. In embodiments, all four IR subarrays may have their own powering scheme so that when they are on itdoes not use full power of main array. In embodiments, a third tier oflower power in binned mode may be used so that these sub arrays could beused as massive pixels for proximity detection applications. In oneembodiment, given that the full field-of-view (FOV) of the main lensmight be as wide as, for example, 120 degrees, for certain sensitiveapplications where one needs to be selectively sensitive to incoming IRlight be specific angles, one may add a micro-optic to guide thisspecific light in. This light guide could be attached to the frame thatholds the main IR cut filter.

In an example embodiment, ground (e.g., 0 V) may be provided to the topcontact 308, and a positive potential may be provided by an off-chipsource (such as the ISP) to the pixel electrodes 304. In an exampleembodiment, the light sensors function as purely passive devices, thatis, they do not consume appreciable power from the image sensor circuit.In an example embodiment, the light sensor consumes power from anexternal device or module, such as an ISP, but does not consumeappreciable power from the image sensor integrated circuit on which thelight sensing film 305 of FIG. 3B is integrated.

In example embodiments, the optically sensitive material 305 of FIG. 3Bmay include a silicon light absorber. In embodiments, this may bereferred to as back-side integration (BSI), a technology that may beemployed to produce image sensors. In embodiments, the peripheral lightsensor may be implemented using a silicon optically sensitive material305. In embodiments, pixels may be connected via the reset gate toprovide current collection. Silicon photodiodes whose current isaggregated such as to the contact 304 of FIG. 3B may be utilized forcurrent (hence, light level) monitoring.

In embodiments, an image sensor integrated circuit comprises at least afirst light sensing region comprised of small and independent pixels,and a second light sensing region comprised of larger pixels, or highlybinned (current-combined) regions. For example, in the image sensorarray region, pixels may have 1.1 μm×1.1 μm dimensions. 0.7 μm×0.7 μmdimensions, or 0.9 μm×0.9 μm dimensions; and peripheral light sensingregions may aggregate current over a much larger area, such as 10 μm×10μm, or 100 μm×100 μm. In embodiments, the ratio of the area of theperipheral light sensing regions to the size of the independent pixelsin the image array region may exceed 100:1. The use of large areas forlight sensing in peripheral regions may facilitate the use of simple,low-cost, and/or off-integrated-circuit biasing and current metering.Embodiments of the disclosed subject matter herein include image sensingcircuits that comprise, on a single semiconductor die, both an imagesensor array, and also at least one independent light sensor powered andread using an independent circuit.

An example embodiment of low power light sensing system comprises aphotosensor able to absorb photons and thereby produce a photocurrentthat is related to incident light intensity. The photosensor may be madeusing the photosensitive material as that which comprises the imagesensing region. In alternative embodiments, it may employ aphotosensitive that is distinct from that used in the image sensingregion.

An example implementation of a low power light sensing system comprisesa photosensor that absorbs photons and produces a current that varies inrelation with incident light intensity. The photosensor can be madeusing the same photosensitive material that comprises the imager pixelarray. Alternatively, dedicated regions of photosensitive material andconstitute photosensor regions. These can potentially be outside of themain image sensing region.

In an example embodiment, a low-power mode may be provided in which thecircuitry associated with the image sensing array region are powereddown. In embodiments, readout circuits may be powered down with theexception of the pixel reset transistor driver circuit, which willprovide the signal necessary to keep pixels in reset (e.g., a GlobalReset state).

In embodiments, the photosensor regions are constantly connected to areset supply. An example embodiment of a reset supply may be on-chipinternally generated.

An example embodiment of a reset supply may be externally generated. Thephotosensor regions can reside directly atop regions of readoutcircuitry that are associated not with reading the photosensor, butinstead with performing other chip functions. Other chip functions mayinclude the readout of at least one pixel comprising the image sensingarray region.

In embodiments, a common optically sensitive material may overlie boththe image sensing regions, and also the photosensing regions. Inembodiments, the optically sensitive layer is in turn covered with abiasing electrode. In embodiments, this biasing electrode is drivenusing a voltage source generated on-chip. In embodiments, this biasingelectrode is driven using an externally provided voltage source. Thephotosensing regions are biased to provide an electric potential betweenthe top and bottom (pixel) electrodes. The current flowing through thetop contact voltage source is related to the light intensity incident onthe photosensing region. Ambient light levels can therefore be monitoredby measuring this current.

In embodiments, the photocurrent can be monitored internally usingon-chip circuitry. In an alternative embodiment, the photocurrent can bemonitored externally using discrete devices.

In embodiments, the pixels or adjacent areas can be subdivided insmaller regions connected to different current monitors to produceindependent measurements of spatially distributed areas.

In embodiments, such data can be used to detect motion, implementgesture control, or refine the quality of the ambient light measurement.

In embodiments, sensing is provided via a dedicated voltage supply forthe drain of the pixels reset transistor. In embodiments, thecorresponding current, i, can be monitored and the variation of currentthrough this supply measured using on-chip or off chip circuitry. Inembodiments, a low-power light-sensing mode is implemented by poweringdown the circuitry associated with the image sensing region; andretaining power to the reset transistor drivers, and, in the case offour transistor (4T) or multiple transistor pixels, also to the transfergate drivers. The total current through the reset transistors of thepixel array can be monitored through the global reset supply. Thecurrent flowing though this voltage source is related to the lightimpinging on the photosensing region, enabling ambient light to bemonitored by measuring this current.

In embodiments such data can be used to detect motion, implement gesturecontrol or refine the quality of the ambient light measurement.

Referring to FIG. 7, example embodiments provide image sensing regionsthat use an array of pixel elements to detect an image. The pixelelements may include photosensitive material. The image sensor maydetect a signal from the photosensitive material in each of the pixelregions that varies based on the intensity of light incident on thephotosensitive material. In one example embodiment, the photosensitivematerial is a continuous film of interconnected nanoparticles.Electrodes are used to apply a bias across each pixel area. Pixelcircuitry is used to integrate a signal in a charge store over a periodof time for each pixel region. The circuit stores an electrical signalproportional to the intensity of light incident on the opticallysensitive layer during the integration period. The electrical signal canthen be read from the pixel circuitry and processed to construct adigital image corresponding to the light incident on the array of pixelelements. In example embodiments, the pixel circuitry may be formed onan integrated circuit device below the photosensitive material. Forexample, a nanocrystal photosensitive material may be layered over aCMOS integrated circuit device to form an image sensor. Metal contactlayers from the CMOS integrated circuit may be electrically connected tothe electrodes that provide a bias across the pixel regions. U.S. patentapplication Ser. No. 12/10,625, titled “Materials, Systems and Methodsfor Optoelectronic Devices,” filed Apr. 18, 2008 (Publication No.20090152664) includes additional descriptions of optoelectronic devices,systems and materials that may be used in connection with exampleembodiments and is hereby incorporated herein by reference in itsentirety. This is an example embodiment only and other embodiments mayuse different photodetectors and photosensitive materials. For example,embodiments may use silicon or Gallium Arsenide (GaAs) photodetectors.

Image sensors incorporate arrays of photodetectors. These photodetectorssense light, converting it from an optical to an electronic signal. FIG.7 shows structure of and areas relating to quantum dot pixel chipstructures (QDPCs) 100, according to example embodiments. As illustratedin FIG. 7, the QDPC 100 may be adapted as a radiation 1000 receiverwhere quantum dot structures 1100 are presented to receive the radiation1000, such as light. The QDPC 100 includes, as will be described in moredetail herein, quantum dot pixels 1800 and a chip 2000 where the chip isadapted to process electrical signals received from the quantum dotpixel 1800. The quantum dot pixel 1800 includes the quantum dotstructures 1100 include several components and sub components such asquantum dots 1200, quantum dot materials 200 and particularconfigurations or quantum dot layouts 300 related to the dots 1200 andmaterials 200. The quantum dot structures 1100 may be used to createphotodetector structures 1400 where the quantum dot structures areassociated with electrical interconnections 1404. The electricalconnections 1404 are provided to receive electric signals from thequantum dot structures and communicate the electric signals on to pixelcircuitry 1700 associated with pixel structures 1500. Just as thequantum dot structures 1100 may be laid out in various patterns, bothplanar and vertical, the photodetector structures 1400 may haveparticular photodetector geometric layouts 1402. The photodetectorstructures 1400 may be associated with pixel structures 1500 where theelectrical interconnections 1404 of the photodetector structures areelectrically associated with pixel circuitry 1700. The pixel structures1500 may also be laid out in pixel layouts 1600 including vertical andplanar layouts on a chip 2000 and the pixel circuitry 1700 may beassociated with other components 1900, including memory for example. Thepixel circuitry 1700 may include passive and active components forprocessing of signals at the pixel 1800 level. The pixel 1800 isassociated both mechanically and electrically with the chip 2000. Inexample embodiments, the pixel structures 1500 and pixel circuitry 1700include structures and circuitry for film binning and/or circuit binningof separate color elements for multiple pixels as described herein. Froman electrical viewpoint, the pixel circuitry 1700 may be incommunication with other electronics (e.g., chip processor 2008). Theother electronics may be adapted to process digital signals, analogsignals, mixed signals and the like and it may be adapted to process andmanipulate the signals received from the pixel circuitry 1700. In otherembodiments, a chip processor 2008 or other electronics may be includedon the same semiconductor substrate as the QDPCs and may be structuredusing a system-on-chip architecture. The other electronics may includecircuitry or software to provide digital binning in example embodiments.The chip 2000 also includes physical structures 2002 and otherfunctional components 2004, which will also be described in more detailbelow.

The QDPC 100 detects electromagnetic radiation 1000, which inembodiments may be any frequency of radiation from the electromagneticspectrum. Although the electromagnetic spectrum is continuous, it iscommon to refer to ranges of frequencies as bands within the entireelectromagnetic spectrum, such as the radio band, microwave band,infrared band (IR), visible band (VIS), ultraviolet band (UV), X-rays,gamma rays, and the like. The QDPC 100 may be capable of sensing anyfrequency within the entire electromagnetic spectrum; however,embodiments herein may reference certain bands or combinations of bandswithin the electromagnetic spectrum. It should be understood that theuse of these bands in discussion is not meant to limit the range offrequencies that the QDPC 100 may sense, and are only used as examples.Additionally, some bands have common usage sub-bands, such as nearinfrared (NIR) and far infrared (FIR), and the use of the broader bandterm, such as IR, is not meant to limit the QDPCs 100 sensitivity to anyband or sub-band. Additionally, in the following description, terms suchas “electromagnetic radiation,” “radiation,” “electromagnetic spectrum,”“spectrum,” “radiation spectrum,” and the like are used interchangeably,and the term color is used to depict a select band of radiation 1000that could be within any portion of the radiation 1000 spectrum, and isnot meant to be limited to any specific range of radiation 1000 such asin visible ‘color’.

In the example embodiment of FIG. 7, the nanocrystal materials andphotodetector structures described above may be used to provide quantumdot pixels 1800 for a photosensor array, image sensor or otheroptoelectronic device. In example embodiments, the pixels 1800 includequantum dot structures 1100 capable of receiving radiation 1000,photodetectors structures adapted to receive energy from the quantum dotstructures 1100 and pixel structures. The quantum dot pixels describedherein can be used to provide the following in some embodiments: highfill factor, color binning, potential to stack, potential to go to smallpixel sizes, high performance from larger pixel sizes, simplify colorfilter array, elimination of de-mosaicing, self-gain setting/automaticgain control, high dynamic range, global shutter capability,auto-exposure, local contrast, speed of readout, low noise readout atpixel level, ability to use larger process geometries (lower cost),ability to use generic fabrication processes, use digital fabricationprocesses to build analog circuits, adding other functions below thepixel such as memory, A to D, true correlated double sampling, binning,etc. Example embodiments may provide some or all of these features.However, some embodiments may not use these features.

A quantum dot 1200 may be a nanostructure, typically a semiconductornanostructure that confines a conduction band electrons, valence bandholes, or excitons (bound pairs of conduction band electrons and valenceband holes) in all three spatial directions. A quantum dot exhibits inits absorption spectrum the effects of the discrete quantized energyspectrum of an idealized zero-dimensional system. The wave functionsthat correspond to this discrete energy spectrum are typicallysubstantially spatially localized within the quantum dot, but extendover many periods of the crystal lattice of the material.

FIG. 8 shows an example of a quantum dot 1200. In one exampleembodiment, the QD 1200 has a core 1220 of a semiconductor or compoundsemiconductor material, such as PbS. Ligands 1225 may be attached tosome or all of the outer surface or may be removed in some embodimentsas described further below. In some embodiments, the cores 1220 ofadjacent QDs may be fused together to form a continuous film ofnanocrystal material with nanoscale features. In other embodiments,cores may be connected to one another by linker molecules.

Some embodiments of the QD optical devices are single image sensor chipsthat have a plurality of pixels, each of which includes a QD layer thatis radiation 1000 sensitive, e.g., optically active, and at least twoelectrodes in electrical communication with the QD layer. The currentand/or voltage between the electrodes is related to the amount ofradiation 1000 received by the QD layer. Specifically, photons absorbedby the QD layer generate electron-hole pairs, such that, if anelectrical bias is applied, a current flows. By determining the currentand/or voltage for each pixel, the image across the chip can bereconstructed. The image sensor chips have a high sensitivity, which canbe beneficial in low-radiation-detecting 1000 applications; a widedynamic range allowing for excellent image detail; and a small pixelsize. The responsivity of the sensor chips to different opticalwavelengths is also tunable by changing the size of the QDs in thedevice, by taking advantage of the quantum size effects in QDs. Thepixels can be made as small as 1 square micron or less, or as large as30 microns by 30 microns or more or any range subsumed therein.

The photodetector structure 1400 of FIGS. 7 and 9 is a device configuredso that it can be used to detect radiation 1000 in example embodiments.The detector may be ‘tuned’ to detect prescribed wavelengths ofradiation 1000 through the types of quantum dot structures 1100 that areused in the photodetector structure 1400. The photodetector structurecan be described as a quantum dot structure 1100 with an I/O for someinput/output ability imposed to access the quantum dot structures' 1100state. Once the state can be read, the state can be communicated topixel circuitry 1700 through an electrical interconnection 1404, whereinthe pixel circuitry may include electronics (e.g., passive and/oractive) to read the state. In an embodiment, the photodetector structure1400 may be a quantum dot structure 1100 (e.g., film) plus electricalcontact pads so the pads can be associated with electronics to read thestate of the associated quantum dot structure.

In embodiments, processing may include binning of pixels in order toreduce random noise associated with inherent properties of the quantumdot structure 1100 or with readout processes. Binning may involve thecombining of pixels 1800, such as creating 2×2, 3×3, 5×5, or the likesuperpixels. There may be a reduction of noise associated with combiningpixels 1800, or binning, because the random noise increases by thesquare root as area increases linearly, thus decreasing the noise orincreasing the effective sensitivity. With the QDPC's 100 potential forvery small pixels, binning may be utilized without the need to sacrificespatial resolution, that is, the pixels may be so small to begin withthat combining pixels doesn't decrease the required spatial resolutionof the system. Binning may also be effective in increasing the speedwith which the detector can be run, thus improving some feature of thesystem, such as focus or exposure. In example embodiments, binning maybe used to combine subpixel elements for the same color or range ofradiation (including UV and/or IR) to provide separate elements for asuperpixel while preserving color/UV/IR resolution as further describedbelow.

In embodiments the chip may have functional components that enablehigh-speed readout capabilities, which may facilitate the readout oflarge arrays, such as 5 Mpixels, 6 Mpixels, 8 Mpixels, 12 Mpixels, orthe like. Faster readout capabilities may require more complex, largertransistor-count circuitry under the pixel 1800 array, increased numberof layers, increased number of electrical interconnects, widerinterconnection traces, and the like.

In embodiments, it may be desirable to scale down the image sensor sizein order to lower total chip cost, which may be proportional to chiparea. However, shrinking chip size may mean, for a given number ofpixels, smaller pixels. In existing approaches, since radiation 1000must propagate through the interconnect layer onto the monolithicallyintegrated silicon photodiode lying beneath, there is a fill-factorcompromise, whereby part of the underlying silicon area is obscured byinterconnect; and, similarly, part of the silicon area is consumed bytransistors used in read-out. One workaround is micro-lenses, which addcost and lead to a dependence in photodiode illumination on positionwithin the chip (center vs. edges); another workaround is to go tosmaller process geometries, which is costly and particularly challengingwithin the image sensor process with its custom implants.

In embodiments, the technology discussed herein may provide a way aroundthese compromises. Pixel size, and thus chip size, may be scaled downwithout decreasing fill factor. Larger process geometries may be usedbecause transistor size, and interconnect line-width, may not obscurepixels since the photodetectors are on the top surface, residing abovethe interconnect. In the technology proposed herein, large geometriessuch as 0.13 μm and 0.18 μm may be employed without obscuring pixels.Similarly, small geometries such as 90 nm and below may also beemployed, and these may be standard, rather thanimage-sensor-customized, processes, leading to lower cost. The use ofsmall geometries may be more compatible with high-speed digital signalprocessing on the same chip. This may lead to faster, cheaper, and/orhigher-quality image sensor processing on chip. Also, the use of moreadvanced geometries for digital signal processing may contribute tolower power consumption for a given degree of image sensor processingfunctionality.

An example integrated circuit system that can be used in combinationwith the above photodetectors, pixel regions and pixel circuits will nowbe described in connection with FIG. 11. FIG. 11 is a block diagram ofan image sensor integrated circuit (also referred to as an image sensorchip). The chip includes:

-   -   a pixel array (100) in which incident light is converted into        electronic signals, and in which electronic signals are        integrated into charge stores whose contents and voltage levels        are related to the integrated light incident over the frame        period; the pixel array may include color filters and electrode        structures for color film binning as described further below;    -   row and column circuits (110 & 120) which are used to reset each        pixel, and read the signal related to the contents of each        charge store, in order to convey the information related to the        integrated light over each pixel over the frame period to the        outer periphery of the chip; the pixel circuitry may include        circuitry for color binning as described further below;    -   analog circuits (130, 140, 150, 160, 230). The pixel electrical        signal from the column circuits is fed into the        analog-to-digital convert (160) where it is converted into a        digital number representing the light level at each pixel. The        pixel array and ADC are supported by analog circuits that        provide bias and reference levels (130, 140, & 150).    -   digital circuits (170, 180, 190, 200). The Image Enhancement        circuitry (170) provides image enhancement functions to the data        output from ADC to improve the signal to noise ratio. Line        buffer (180) temporarily stores several lines of the pixel        values to facilitate digital image processing and JO        functionality. (190) is a bank of registers that prescribe the        global operation of the system and/or the frame format. Block        200 controls the operation of the chip. The digital circuits may        also include circuits or software for digital color binning;    -   IO circuits (210 & 220) support both parallel input/output and        serial input/output. (210) is a parallel JO interface that        outputs every bit of a pixel value simultaneously. (220) is a        serial JO interface where every bit of a pixel value is output        sequentially.    -   a phase-locked loop (230) provides a clock to the whole chip.

In a particular example embodiment, when 0.11 μm CMOS technology node isemployed, the periodic repeat distance of pixels along the row-axis andalong the column-axis may be 900 nm, 1.1 μm, 1.2 μm, 1.4 μm, 1.75 μm,2.2 μm, or larger. The implementation of the smallest of these pixelssizes, especially 900 nm, 1.1 μm, and 1.2 μm, may require transistorsharing among pairs or larger group of adjacent pixels in someembodiments.

Very small pixels can be implemented in part because all of the siliconcircuit area associated with each pixel can be used for read-outelectronics since the optical sensing function is achieved separately,in another vertical level, by the optically-sensitive layer that residesabove the interconnect layer.

Because the optically sensitive layer and the read-out circuit thatreads a particular region of optically sensitive material exist onseparate planes in the integrated circuit, the shape (viewed from thetop) of (1) the pixel read-out circuit and (2) the optically sensitiveregion that is read by (1); can be generally different. For example itmay be desired to define an optically sensitive region corresponding toa pixel as a square; whereas the corresponding read-out circuit may bemost efficiently configured as a rectangle.

In an imaging array based on a top optically sensitive layer connectedthrough vias to the read-out circuit beneath, there exists no imperativefor the various layers of metal, vias, and interconnect dielectric to besubstantially or even partially optically transparent, although they maybe transparent in some embodiments. This contrasts with the case offront-side-illuminated CMOS image sensors in which a substantiallytransparent optical path must exist traversing the interconnect stack.

Example embodiments include an image sensor circuit that includes animage sensing region (such as FIG. 1A, Main Visible Image Sensor); andat least a first photosensor proximate the image sensor (such as FIG.1A, element numbers (1), (2), etc.). The at least one photosensorincludes a light-sensitive region that resides outside of the imagesensing region. In a first mode, control circuitry is configured to readout image data from the image sensing region that is indicative of animage incident on image sensing region. In a second mode, the circuitryis configured to read out a signal from the at least first photosensor.This current is indicative of intensity of light incident on thelight-sensitive region of the first photosensor. In embodiments, thetotal power consumed by the integrated circuit in the first mode mayexceed 100 mW. In embodiments, the total power consumed by theintegrated circuit in the second mode may be less than 10 mW. In thepreceding sentences, the total integrated circuit power may be definedas the total electrical power transferred to the integrated circuit(typically the sum of all time-averaged current*voltage products at allnodes connected to external power circuitry). In embodiments, the imagesensor and the at least one photosensor are fabricated atop a singlepiece of monolithic silicon, that is, atop a single substrate, a singledie.

Embodiments include an integrated circuit comprising a semiconductorsubstrate; an image sensing region (such as FIG. 1A, Main Visible ImageSensor) that includes a plurality of optically-sensitive pixel regions(such as FIG. 9, the multiple regions 1403 each constituting a pixelelectrode collecting photocharges from an overlying optically sensitivematerial); a pixel circuit comprising circuitry formed on thesemiconductor substrate for each pixel region, each pixel circuitcomprising a charge store and a read-out circuit (such as shown in FIG.10); and a photosensor region outside of the image sensing region (suchas FIG. 1A, element numbers (1), (2), etc.); and a read-out circuit forthe photosensitive region configured to read out a signal from thephotosensor region that is indicative of intensity of light incidentphotosensitive region of the photosensor. In embodiments, the firstphotosensitive region (FIG. 1A, element number (1)) may offer a distinctfield of view different from the field of view offered by a secondphotosensitive region (FIG. 1A, element number (2)).

Pixel circuitry may be defined to include components beginning at theelectrodes in contact with the quantum dot material 200 and ending whensignals or information is transferred from the pixel to other processingfacilities, such as the functional components 2004 of the underlyingchip 200 or another quantum dot pixel 1800. Beginning at the electrodeson the quantum dot material 200, the signal is translated or read. Inembodiments, the quantum dot material 200 may provide a change incurrent flow in response to radiation 1000. The quantum dot pixel 1800may require bias circuitry 1700 in order to produce a readable signal.This signal in turn may then be amplified and selected for readout. Oneembodiment of a pixel circuit shown in FIG. 10 uses a reset-biastransistor 1802, amplifier transistor 1804, and column addresstransistor 1808. This three-transistor circuit configuration may also bereferred to as a 3T circuit. Here, the reset-bias transistor 1802connects the bias voltage 1702 to the photoconductive photovoltaicquantum dot material 200 when reset 1704 is asserted, thus resetting theelectrical state of the quantum dot material 200. After reset 1704, thequantum dot 26I material 200 may be exposed to radiation 1000, resultingin a change in the electrical state of the quantum dot material 200, inthis instance a change in voltage leading into the gate of the amplifier1804. This voltage is then boosted by the amplifier transistor 1804 andpresented to the address selection transistor 1808, which then appearsat the column output of the address selection transistor 1808 whenselected. In some embodiments, additional circuitry may be added to thepixel circuit to help subtract out dark signal contributions. In otherembodiments, adjustments for dark signal can be made after the signal isread out of the pixel circuit. In example, embodiments, additionalcircuitry may be added for film binning or circuit binning.

Embodiments include a mobile device comprising a semiconductorsubstrate; an image sensing region (FIG. 1A, Main Visible Image Sensor)comprising pixel circuitry (e.g. FIG. 10, and FIG. 11, region 100 PixelArray) formed on the semiconductor substrate and an optically sensitivematerial; a photosensor comprising read-out circuitry formed on thesemiconductor substrate and a light sensitive region; circuitryconfigured to read-out an image from the image sensor (e.g. FIG. 11, rowCircuit 120); a processor configured to process a signal read-out fromthe photosensor for gesture recognition, facial recognition, motiondetection using light reflected from the scene and sensed by thephotosensor; and control circuitry configured in at least one mode toprovide power to read out the photosensor without providing power toread out the image sensing region; such that power consumption isreduced compared to a mode where the power is provided to operate theimage sensing region. For example, in the mode when the image sensingregion is operated and read and digital data are output corresponding tothe image it detects, integrated circuit power may exceed 100 mW;whereas in the mode in which the photosensing regions are used tomonitor events, gestures, motion, etc., integrated circuit power may bebelow 10 mW.

FIG. 12 shows an embodiment of a single-plane computing device 100 thatmay be used in computing, communication, gaming, interfacing, and so on.The single-plane computing device 100 is shown to include a peripheralregion 101 and a display region 103. A touch-based interface device 117,such as a button or touchpad, may be used in interacting with thesingle-plane computing device 100.

An example of a first camera module 113 is shown to be situated withinthe peripheral region 101 of the single-plane computing device 100 andis described in further detail, below. Example light sensors 115A, 115Bare also shown to be situated within the peripheral region 101 of thesingle-plane computing device 100 and are described in further detail,below, with reference to FIG. 15. An example of a second camera module105 is shown to be situated in the display region 103 of thesingle-plane computing device 100 and is described in further detail,below, with reference to FIG. 14.

Examples of light sensors 107A, 107B, shown to be situated in thedisplay region 103 of the single-plane computing device 100 and aredescribed in further detail, below, with reference to FIG. 15. Anexample of a first source of optical illumination 111 (which may bestructured or unstructured) is shown to be situated within theperipheral region 101 of the single-plane computing device 100. Anexample of a second source of optical illumination 109 is shown to besituated in the display region 103.

In embodiments, the display region 103 may be a touchscreen display. Inembodiments, the single-plane computing device 100 may be a tabletcomputer. In embodiments, the single-plane computing device 100 may be amobile handset.

FIG. 13 shows an embodiment of a double-plane computing device 200 thatmay be used in computing, communication, gaming, interfacing, and so on.The double-plane computing device 200 is shown to include a firstperipheral region 201A and a first display region 203A of a first plane210, a second peripheral region 201B and a second display region 203B ofa second plane 230, a first touch-based interface device 217A of thefirst plane 210 and a second touch-based interface device 217B of thesecond plane 230. The example touch-based interface devices 217A, 217Bmay be buttons or touchpads that may be used in interacting with thedouble-plane computing device 200. The second display region 203B mayalso be an input region in various embodiments.

The double-plane computing device 200 is also shown to include examplesof a first camera module 213A in the first peripheral region 201A and asecond camera module 213B in the second peripheral region 201B. Thecamera modules 213A, 213B are described in more detail, below, withreference to FIG. 14. As shown, the camera modules 213A, 213B aresituated within the peripheral regions 201A, 201B of the double-planecomputing device 200. Although a total of two camera modules are shown,a person of ordinary skill in the art will recognize that more or fewerlight sensors may be employed.

A number of examples of light sensors 215A, 215B, 215C, 215D, are shownsituated within the peripheral regions 201A, 201B of the double-planecomputing device 200. Although a total of four light sensors are shown,a person of ordinary skill in the art will recognize that more or fewerlight sensors may be employed. Examples of the light sensors 215A, 215B,215C, 215D, are described, below, in further detail with reference toFIG. 4. As shown, the light sensors 215A, 215B, 215C, 215D, are situatedwithin the peripheral regions 201A, 201B of the double-plane computingdevice 200.

The double-plane computing device 200 is also shown to include examplesof a first camera module 205A in the first display region 203A and asecond camera module 205B in the second display region 203B. The cameramodules 205A, 205B are described in more detail, below, with referenceto FIG. 14. As shown, the camera modules 205A, 205B are situated withinthe display regions 203A, 203B of the double-plane computing device 200.Also shown as being situated within the display regions 203A, 203B ofthe double-plane computing device 200 are examples of light sensors207A, 207B, 207C, 207D. Although a total of four light sensors areshown, a person of ordinary skill in the art will recognize that more orfewer light sensors may be employed. Examples of the light sensors 207A,207B, 207C, 207D are described, below, in further detail with referenceto FIG. 15. Example sources of optical illumination 211A, 211B are shownsituated within the peripheral region 201A, 201B and other examplesources of optical illumination 209A, 209B are shown situated within oneof the display regions 203A, 203B and are also described with referenceto FIG. 15, below. A person of ordinary skill in the art will recognizethat various numbers and locations of the described elements, other thanthose shown or described, may be implemented.

In embodiments, the double-plane computing device 200 may be a laptopcomputer. In embodiments, the double-plane computing device 200 may be amobile handset.

With reference now to FIG. 14, an embodiment of a camera module 300 thatmay be used with the computing devices of FIG. 12 or FIG. 13 is shown.The camera module 300 may correspond to the camera module 113 of FIG. 12or the camera modules 213A, 213B of FIG. 13. As shown in FIG. 14, thecamera module 300 includes a substrate 301, an image sensor 303, andbond wires 305. A holder 307 is positioned above the substrate. Anoptical filter 309 is shown mounted to a portion of the holder 307. Abarrel 311 holds a lens 313 or a system of lenses.

FIG. 15 shows an embodiment of a light sensor 400 that may be used withthe computing devices of FIG. 12 or FIG. 13 an example embodiment of alight sensor. The light sensor 400 may correspond to the light sensors115A, 115B of FIG. 12 of the light sensors 215A, 215B, 215C, 215D ofFIG. 13. The light sensor 400 is shown to include a substrate 401, whichmay correspond to a portion of either or both of the peripheral region101 or the display region 103 of FIG. 12. The substrate 401 may alsocorrespond to a portion of either or both of the peripheral regions201A, 201B or the display regions 203A, 203B of FIG. 13. The lightsensor 400 is also shown to include electrodes 403A, 403B used toprovide a bias across light-absorbing material 405 and to collectphotoelectrons therefrom. An encapsulation material 407 or a stack ofencapsulation materials is shown over the light-absorbing material 405.Optionally, the encapsulation material 407 may include conductiveencapsulation material for biasing and/or collecting photoelectrons fromthe light-absorbing material 405.

Elements of a either the single-plane computing device 100 of FIG. 12,or the double-plane computing device 200 of FIG. 13, may be connected orotherwise coupled with one another. Embodiments of the computing devicesmay include a processor. It may include functional blocks, and/orphysically distinct components, that achieve computing, imageprocessing, digital signal processing, storage of data, communication ofdata (through wired or wireless connections), the provision of power todevices, and control of devices. Devices that are in communication withthe processor include devices of FIG. 12 may include the display region103, the touch-based interface device 117, the camera modules 105, 113,the light sensors 115A, 115B, 107A, 107B, and the sources of opticalillumination 109, 111. Similarly correspondences may apply to FIG. 13 aswell.

The light sensor of FIG. 15 may include a light-absorbing material 405of various designs and compositions. In embodiments, the light-absorbingmaterial may be designed to have an absorbance that is sufficientlysmall, across the visible wavelength region approximately 450 nm to 650nm, such that, in cases in which the light sensor of FIG. 15 isincorporated into the display region of a computing device, only amodest fraction of visible light incident upon the sensor is absorbed bythe light-absorbing material. In this case, the quality of the imagesdisplayed using the display region is not substantially compromised bythe incorporation of the light-absorbing material along the optical pathof the display. In embodiments, the light-absorbing material 405 mayabsorb less than 30%, or less than 20%, or less than 10%, of lightimpinging upon it in across the visible spectral region.

In embodiments, the electrodes 403A, 403B, and, in the case of aconductive encapsulant for 407, the top electrode 407, may beconstituted using materials that are substantially transparent acrossthe visible wavelength region approximately 450 nm to 650 nm. In thiscase, the quality of the images displayed using the display region isnot substantially compromised by the incorporation of thelight-absorbing material along the optical path of the display.

In embodiments, the light sensor of FIG. 15 may include a light-sensingmaterial capable of sensing infrared light. In embodiments, thelight-sensing material may be a semiconductor having a bandgapcorresponding to an infrared energy, such as in the range 0.5 eV-1.9 eV.In embodiments, the light-sensing material may have measurableabsorption in the infrared spectral range; and may have measurableabsorption also in the visible range. In embodiments, the light-sensingmaterial may absorb a higher absorbance in the visible spectral range asin the infrared spectral range; yet may nevertheless be used to sensegesture-related signals in the infrared spectral range.

In an example embodiment, the absorbance of the light-sensingdisplay-incorporated material may lie in the range 2-20% in the visible;and may lie in the range 0.1-5% in the infrared. In an exampleembodiment, the presence of visible light in the ambient, and/or emittedfrom the display, may produce a background signal within the lightsensor, as a consequence of the material visible-wavelength absorptionwithin the light-absorbing material of the light sensor. In an exampleembodiment, sensing in the infrared region may also be achieved. Thelight sources used in aid of gesture recognition may be modulated usingspatial, or temporal, codes, allowing them to be distinguished from thevisible-wavelength-related component of the signal observed in the lightsensor. In an example embodiment, at least one light source used in aidof gesture recognition may be modulated in time using a code having afrequency component greater than 100 Hz, 1000 Hz, 10 kHz, or 100 kHz. Inan example embodiment, the light sensor may have a temporal responsehaving a cutoff frequency greater than said frequency components. Inembodiments, circuitry may be employed to ensure that the frequencycomponent corresponding to gesture recognition can be extracted andmonitored, with the background components related to the room ambient,the display illumination, and other such non-gesture-related backgroundinformation substantially removed. In this example, the light sensors,even though they absorb both visible and infrared light, can provide asignal that is primarily related to gestural information of interest ingesture recognition.

In an example embodiment, an optical source having a total optical powerof approximately 1 mW may be employed. When illuminating an object adistance approximately 10 cm away, where the object has areaapproximately 1 cm² and diffuse reflectance approximately 20%, then theamount of power incident on a light sensor having area 1 cm2 may be oforder 100 pW. In an example embodiment, a light sensor having absorbanceof 1% may be employed, corresponding to a photocurrent related to thelight received as a consequence of the illumination via the opticalsource, and reflected or scattered off of the object, and thus incidentonto the light sensor, may therefore be of order pW. In exampleembodiments, the electrical signal reported by the light sensor maycorrespond to approximately pA signal component at the modulationfrequency of the optical source. In example embodiments, a largeadditional signal component, such as in the nA or μA range, may arisedue to visible and infrared background, display light, etc. In exampleembodiments, the relatively small signal components, with itsdistinctive temporal and/or spatial signature as provided by modulation(in time and/or space) of the illumination source, may nevertheless beisolated relative to other background/signal, and may be employed todiscern gestural information.

In embodiments, light-absorbing material 405 may consist of a materialthat principally absorbs infrared light in a certain band; and that issubstantially transparent to visible-wavelength light. In an exampleembodiment, a material such as PBDTT-DPP, the near-infraredlight-sensitive polymerpoly(2,60-4,8-bis(5-ethylhexylthienyl)benzo-[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione),may be employed as a component of the light-absorbing layer.

In embodiments, the electronic signal produced by the light sensor maybe communicated to a device for electronic amplification. This devicemay amplify a specific electronic frequency band more than other bands,producing an enhanced signal component that is related to the gesturalinformation. The signal from the light sensor, possibly with thecombination of amplification (potentially frequency-dependent), may beinput to an analog-to-digital converter that can produce a digitalsignal related to the gestural information. The digital informationrelated to gestural information can be further conveyed to otherintegrated circuits and/or signal processing engines in the context of asystem. For example, it may be conveyed to an application processor.

In embodiments, optical sources used to illuminate a volume of space,with the goal of enabling gesture recognition, may use illumination at anear infrared wavelength that is substantially unseen by the human eye.In an example embodiment, a light-emitting diode having centerwavelength of approximately 950 nm may be employed.

In embodiments, gesture recognition may be accomplished by combininginformation from at least one camera, embedded into the computingdevice, and having a lens providing a substantially focused image ontoan image sensor that is part of the camera; and may also incorporatesensors in the peripheral region, and/or integrated into the displayregion. In embodiments, the distributed sensors may provide generalinformation on the spatio-temporal movements of the object being imaged;and the signals from the at least one camera(s) may be combined with thedistributed sensors' signals to provide a morespatially-/temporally-accurate picture of the two- or three-dimensionalmotion of the object whose gesture is to be recognized. In an exampleembodiment, the camera may employ an image sensor providing a modestspatial resolution, such as QVGA, VGA, SVGA, etc., and thus beimplemented using an image sensor having small die size and thus lowcost; and also be implemented using a camera module having small x, y,and z form factor, enabling minimal consumption of peripheral regionarea, and no substantial addition to the z-height of the tablet or othercomputing device. In embodiments, a moderate frame rate, such as 15 fps,30 fps, or 60 fps may be employed, which, combined with a modestresolution, enables a low-cost digital communication channel andmoderate complexity of signal processing in the recognition of gestures.In embodiments, the at least one camera module may implement wide fieldof view imaging in order to provide a wide angular range in theassessment of gestures in relation to a display. In embodiments, atleast one camera module may be tilted, having its angle of regardnonparallel to the normal direction (perpendicular direction) to thedisplay, enabling the at least one camera to image an angular extent incloser proximity to the display. In embodiments, multiple cameras may beemployed in combination, each having an angle of regard distinct from atleast one another, thereby enabling gestures in moderate proximity tothe display to be imaged and interpreted. In embodiments, the at leastone camera may employ an image sensor sensitized using light-detectingmaterials that provide high quantum efficiency, for example, greaterthan 30%, at near infrared wavelength used by the illuminating source;this enables reduced requirement for power and/or intensity in theilluminating source. In embodiments, the illuminating source may bemodulated in time at a specific frequency and employing a specifictemporal pattern (e.g., a series of pulses of known spacing and width intime); and the signal from the at least one camera and/or the at leastone distributed sensor may be interpreted with knowledge of the phaseand temporal profile of the illuminating source; and in this manner,increased signal-to-noise ratio, akin to lock-in or boxcar-averaging orother filtering and/or analog or digital signal processing methods, maybe used to substantially pinpoint the moduled, hence illuminated signal,and substantially remove or minimize the background signal associatedwith the background scene.

FIG. 16 shows an embodiment of a method of gesture recognition. Themethod comprises an operation 501 that includes acquiring a stream intime of at least two images from each of at least one of the cameramodule(s); and an operation 507 that includes also acquiring a stream,in time, of at least two signals from each of at least one of the lightsensors. The method further comprises, at operations 503 and 509,conveying the images and/or signals to a processor. The method furthercomprises, at operation 505, using the processor, an estimate of agesture's meaning, and timing, based on the combination of the imagesand signals.

FIG. 17 shows an embodiment of a method of gesture recognition. Themethod comprises an operation 601 that includes acquiring a stream intime of at least two images from each of at least one of the cameramodules; and an operation 607 that includes also acquiring a stream, intime, of at least two signals from each of at least one of thetouch-based interface devices. The method further comprises, atoperations 603 and 609, conveying the images and/or signals to aprocessor. The method further comprises, at operation 605, using theprocessor, an estimate of a gesture's meaning, and timing, based on thecombination of the images and signals.

In embodiments, signals received by at least one of (1) the touch-basedinterface devices; (2) the camera modules; (3) the light sensors, eachof these either within the peripheral and/or the display ordisplay/input regions, may be employed and, singly or jointly, used todetermine the presence, and the type, of gesture indicated by a user ofthe device.

Referring again to FIG. 16, in embodiments, a stream, in time, of imagesis acquired from each of at least one of the camera modules. A stream,in time, of at least two signals from each of at least one of the lightsensors is also acquired. In embodiments, the streams may be acquiredfrom the different classes of peripheral devices synchronously. Inembodiments, the streams may be acquired with known time stampsindicating when each was acquired relative to the others, for example,to some conference reference time point. In embodiments, the streams areconveyed to a processor. The processor computes an estimate of thegesture's meaning, and timing, based on the combination of the imagesand signals.

In embodiments, at least one camera module has a wide field of viewexceeding about 40°. In embodiments, at least one camera module employsa fisheye lens. In embodiments, at least one image sensor achieveshigher resolution at its center, and lower resolution in its periphery.In embodiments, at least one image sensor uses smaller pixels near itscenter and larger pixels near its periphery.

In embodiments, active illumination via at least one light source;combined with partial reflection and/or partial scattering off of aproximate object; combined with light sensing using at least one opticalmodule or light sensor; may be combined to detect proximity to anobject. In embodiments, information regarding such proximity may be usedto reduce power consumption of the device. In embodiments, powerconsumption may be reduced by dimming, or turning off, power-consumingcomponents such as a display.

In embodiments, at least one optical source may emit infrared light. Inembodiments, at least one optical source may emit infrared light in thenear infrared between about 700 nm and about 1100 nm. In embodiments, atleast one optical source may emit infrared light in the short-wavelengthinfrared between about 1100 nm and about 1700 nm wavelength. Inembodiments, the light emitted by the optical source is substantiallynot visible to the user of the device.

In embodiments, at least one optical source may project a structuredlight image. In embodiments, spatial patterned illumination, combinedwith imaging, may be employed to estimate the relative distance ofobjects relative to the imaging system.

In embodiments, at least two lensing systems may be employed to image ascene, or portions of a scene, onto two distinct regions of amonolithically-integrated single image sensor integrated circuit; andthe patterns of light thus acquired using the image sensor integratedcircuit may be used to aid in estimating the relative or absolutedistances of objects relative to the image sensor system.

In embodiments, at least two lensing systems may be employed to image ascene, or portions of a scene, onto two distinct image sensor integratedcircuits housed within a single camera system; and the patterns of lightthus acquired using the image sensor integrated circuits may be used toaid in estimating the relative or absolute distances of objects relativeto the image sensor system.

In embodiments, at least two lensing systems may be employed to image ascene, or portions of a scene, onto two distinct image sensor integratedcircuits housed within separate camera systems or subsystems; and thepatterns of light thus acquired using the image sensor integratedcircuits may be used to aid in estimating the relative or absolutedistances of objects relative to the image sensor systems or subsystems.

In embodiments, the different angles of regard, or perspectives, fromwhich the at least two optical systems perceive the scene, may be usedto aid in estimating the relative or absolute distances of objectsrelative to the image sensor system.

In embodiments, light sensors such as the light sensors 115A, 115Bsituated in the peripheral region 101 of FIG. 12, and/or the lightsensors 107A, 107B situated in the display region 103 of FIG. 12, may beused singly, or in combination with one another, and/or in combinationwith camera modules, to acquire information about a scene. Inembodiments, light sensors may employ lenses to aid in directing lightfrom certain regions of a scene onto specific light sensors. Inembodiments, light sensors may employ systems for aperturing, such aslight-blocking housings, that define a limited angular range over whichlight from a scene will impinge on a certain light sensor. Inembodiments, a specific light sensor will, with the aid of aperturing,be responsible for sensing light from within a specific angular cone ofincidence.

In embodiments, the different angles of regard, or perspectives, fromwhich the at least two optical systems perceive the scene, may be usedto aid in estimating the relative or absolute distances of objectsrelative to the image sensor system.

In embodiments, the time sequence of light detector from at least twolight sensors may be used to estimate the direction and velocity of anobject. In embodiments, the time sequence of light detector from atleast two light sensors may be used to ascertain that a gesture was madeby a user of a computing device. In embodiments, the time sequence oflight detector from at least two light sensors may be used to classifythe gesture that was made by a user of a computing device. Inembodiments, information regarding the classification of a gesture, aswell as the estimated occurrence in time of the classified gesture, maybe conveyed to other systems or subsystems within a computing device,including to a processing unit.

In embodiments, light sensors may be integrated into the display regionof a computing device, for example, the light sensors 107A, 107B of FIG.12. In embodiments, the incorporation of the light sensors into thedisplay region can be achieved without the operation of the display inthe conveyance of visual information to the user being substantiallyaltered. In embodiments, the display may convey visual information tothe user principally using visible wavelengths in the range of about 400nm to about 650 nm, while the light sensors may acquire visualinformation regarding the scene principally using infrared light ofwavelengths longer than about 650 nm. In embodiments, a ‘display plane’operating principally in the visible wavelength region may reside infront of—closer to the user—than a ‘light sensing plane’ that mayoperate principally in the infrared spectral region.

In embodiments, structured light of a first type may be employed, and ofa second type may also be employed, and the information from the atleast two structured light illuminations may be usefully combined toascertain information regarding a scene that exceeds the informationcontained in either isolated structured light image.

In embodiments, structured light of a first type may be employed toilluminate a scene and may be presented from a first source providing afirst angle of illumination; and structured light of a second type maybe employed to illuminate a scene and may be presented from a secondsource providing a second angle of illumination.

In embodiments, structured light of a first type and a first angle ofillumination may be sensed using a first image sensor providing a firstangle of sensing; and also using a second image sensor providing asecond angle of sensing.

In embodiments, structured light having a first pattern may be presentedfrom a first source; and structured light having a second pattern may bepresented from a second source.

In embodiments, structured light having a first pattern may be presentedfrom a source during a first time period; and structured light having asecond pattern may be presented from a source during a second timeperiod.

In embodiments, structured light of a first wavelength may be used toilluminate a scene from a first source having a first angle ofillumination; and structured light of a second wavelength may be used toilluminate a scene from a second source having a second angle ofillumination.

In embodiments, structured light of a first wavelength may be used toilluminate a scene using a first pattern; and structured light of asecond wavelength may be used to illuminate a scene using a secondpattern. In embodiments, a first image sensor may sense the scene with astrong response at the first wavelength and a weak response at thesecond wavelength; and a second image sensor may sense the scene with astrong response at the second wavelength and a weak response at thefirst wavelength. In embodiments, an image sensor may consist of a firstclass of pixels having strong response at the first wavelength and weakresponse at the second wavelength; and of a second class of pixelshaving strong response at the second wavelength and weak response at thefirst wavelength.

Embodiments include image sensor systems that employ a filter having afirst bandpass spectral region; a first bandblock spectral region; and asecond bandpass spectral region. Embodiments include the first bandpassregion corresponding to the visible spectral region; the first bandblockspectral region corresponding to a first portion of the infrared; andthe second bandpass spectral region corresponding to a second portion ofthe infrared. Embodiments include using a first time period to detectprimarily the visible-wavelength scene; and using active illuminationwithin the second bandpass region during a second time period to detectthe sum of a visible-wavelength scene and an actively-illuminatedinfrared scene; and using the difference between images acquired duringthe two time periods to infer a primarily actively-illuminated infraredscene. Embodiments include using structured light during the second timeperiod. Embodiments include using infrared structured light. Embodimentsinclude using the structured light images to infer depth informationregarding the scene; and in tagging, or manipulating, the visible imagesusing information regarding depth acquired based on the structured lightimages.

In embodiments, gestures inferred may include one-thumb-up;two-thumbs-up; a finger swipe; a two-finger swipe; a three-finger swipe;a four-finger-swipe; a thumb plus one finger swipe; a thumb plus twofinger swipe; etc. In embodiments, gestures inferred may includemovement of a first digit in a first direction; and of a second digit ina substantially opposite direction. Gestures inferred may include atickle.

Sensing of the intensity of light incident on an object may be employedin a number of applications. One such application includes estimation ofambient light levels incident upon an object so that the object's ownlight-emission intensity can be suitable selected. In mobile devicessuch as cell phones, personal digital assistants, smart phones, and thelike, the battery life, and thus the reduction of the consumption ofpower, are of importance. At the same time, the visual display ofinformation, such as through the use of a display such as those based onLCDs or pixellated LEDs, may also be needed. The intensity with whichthis visual information is displayed depends at least partially on theambient illumination of the scene. For example, in very bright ambientlighting, more light intensity generally needs to be emitted by thedisplay in order for the display's visual impression or image to beclearly visible above the background light level. When ambient lightingis weaker, it is feasible to consume less battery power by emitting alower level of light from the display.

As a result, it is of interest to sense the light level near or in thedisplay region. Existing methods of light sensing often include asingle, or a very few, light sensors, often of small area. This can leadto undesired anomalies and errors in the estimation of ambientillumination levels, especially when the ambient illumination of thedevice of interest is spatially inhomogeneous. For example, shadows dueto obscuring or partially obscuring objects may—if they obscure one or afew sensing elements—result in a display intensity that is less brightthan desirable under the true average lighting conditions.

Embodiments include realization of a sensor, or sensors, that accuratelypermit the determination of light levels. Embodiments include at leastone sensor realized using solution-processed light-absorbing materials.Embodiments include sensors in which colloidal quantum dot filmsconstitute the primary light-absorbing element. Embodiments includesystems for the conveyance of signals relating to the light levelimpinging on the sensor that reduce, or mitigate, the presence of noisein the signal as it travels over a distance between a passive sensor andactive electronics that employ the modulation of electrical signals usedin transduction. Embodiments include systems that include (1) thelight-absorbing sensing element; (2) electrical interconnect for theconveyance of signals relating to the light intensity impinging upon thesensing element; and (3) circuitry that is remote from thelight-absorbing sensing element, and is connected to it via theelectrical interconnect, that achieves low-noise conveyance of thesensed signal through the electrical interconnect. Embodiments includesystems in which the length of interconnect is more than one centimeterin length. Embodiments include systems in which interconnect does notrequire special shielding yet achieve practically useful signal-to-noiselevels.

Embodiments include sensors, or sensor systems, that are employed,singly or in combination, to estimate the average color temperatureilluminating the display region of a computing device. Embodimentsinclude sensors, or sensor systems, that accept light from a wideangular range, such as greater than about ±20° to normal incidence, orgreater than about ±30° to normal incidence, or greater than about ±40°to normal incidence. Embodiments include sensors, or sensor systems,that include at least two types of optical filters, a first type passingprimarily a first spectral band, a second type passing primarily asecond spectral band. Embodiments include using information from atleast two sensors employing at least two types of optical filters toestimate color temperature illuminating the display region, or a regionproximate the display region.

Embodiments include systems employing at least two types of sensors.Embodiments include a first type constituted of a first light-sensingmaterial, and a second type constituted of a second light-sensingmaterial. Embodiments include a first light-sensing material configuredto absorb, and transduce, light in a first spectral band, and a secondlight-sensing material configured to transduce a second spectral band.Embodiments include a first light-sensing material employing a pluralityof nanoparticles having a first average diameter, and a secondlight-sensing material employing a plurality of nanoparticles have asecond average diameter. Embodiments include a first diameter in therange of approximately 1 nm to approximately 2 nm, and a second diametergreater than about 2 nm.

Embodiments include methods of incorporating a light-sensing materialinto, or onto, a computing device involving ink-jet printing.Embodiments include using a nozzle to apply light-sensing material overa defined region. Embodiments include defining a primary light-sensingregion using electrodes. Embodiments include methods of fabricatinglight sensing devices integrated into, or onto, a computing deviceinvolving: defining a first electrode; defining a second electrode;defining a light-sensing region in electrical communication with thefirst and the second electrode. Embodiments include methods offabricating light sensing devices integrated into, or onto, a computingdevice involving: defining a first electrode; defining a light-sensingregion; and defining a second electrode; where the light sensing regionis in electrical communication with the first and the second electrode.

Embodiments include integration at least two types of sensors into, oronto, a computing device, using ink jet printing. Embodiments includeusing a first reservoir containing a first light-sensing materialconfigured to absorb, and transduce, light in a first spectral band; andusing a second reservoir containing a second light-sensing materialconfigured to absorb, and transduce, light in a second spectral band.

Embodiments include the use of differential or modulated signaling inorder to substantially suppress any external interference. Embodimentsinclude subtracting dark background noise.

Embodiments include a differential system depicted in FIG. 18. FIG. 18shows an embodiment of a three-electrode differential-layout system 700to reduce external interferences with light sensing operations. Thethree-electrode differential-layout system 700 is shown to include alight sensing material covering all three electrodes 701, 703, 705. Alight-obscuring material 707 (Black) prevents light from impinging uponthe light-sensing material in a region that is electrically accessedusing the first electrode 701 and the second electrode 703. Asubstantially transparent material 709 (Clear) allows light to impingeupon the light-sensing material in a substantially distinct region thatis electrically accessed using the second electrode 703 and the thirdelectrode 705. The difference in the current flowing through theClear-covered electrode pair and the Black-covered electrode pair isequal to the photocurrent—that is, this difference does not include anydark current, but instead is proportional to the light intensity, withany dark offset substantially removed.

Embodiments include the use of a three-electrode system as follows. Eachelectrode consists of a metal wire. Light-absorbing material may be inelectrical communication with the metal wires. Embodiments include theencapsulation of the light-absorbing material using a substantiallytransparent material that protects the light-absorbing material fromambient environmental conditions such as air, water, humidity, dust, anddirt. The middle of the three electrodes may be biased to a voltage V₁,where an example of a typical voltage is about 0 V. The two outerelectrodes may be biased to a voltage V₂, where a typical value is about3 V. Embodiments include covering a portion of the device usinglight-obscuring material that substantially prevents, or reduces, theincidence of light on the light-sensing material.

The light-obscuring material ensures that one pair of electrodes seeslittle or no light. This pair is termed the dark, or reference,electrode pair. The use of a transparent material over the otherelectrode pair ensures that, if light is incident, it is substantiallyincident upon the light-sensing material. This pair is termed the lightelectrode pair.

The difference in the current flowing through the light electrode pairand the dark electrode pair is equal to the photocurrent—that is, thisdifference does not include any dark current, but instead isproportional to the light intensity, with any dark offset substantiallyremoved.

In embodiments, these electrodes are wired in twisted-pair form. In thismanner, common-mode noise from external sources is reduced or mitigated.Referring to FIG. 19, electrodes 801, 803, 805 with twisted pair layout800, the use of a planar analogue of a twisted-pair configuration leadsto reduction or mitigation of common-mode noise from external sources.

In another embodiment, biasing may be used such that the light-obscuringlayer may not be required. The three electrodes may be biased to threevoltages V₁, V₂, and V₃. In one example, V₁=6 V, V₂=3 V, V₃=0 V. Thelight sensor between 6 V and 3 V, and that between 0 V and 3 V, willgenerate opposite-direction currents when read between 6 V and 0 V. Theresultant differential signal is then transferred out in twisted-pairfashion.

In embodiments, the electrode layout may itself be twisted, furtherimproving the noise-resistance inside the sensor. In this case, anarchitecture is used in which an electrode may cross over another.

In embodiments, electrical bias modulation may be employed. Analternating bias may be used between a pair of electrodes. Thephotocurrent that flows will substantially mimic the temporal evolutionof the time-varying electrical biasing. Readout strategies includefiltering to generate a low-noise electrical signal. The temporalvariations in the biasing include sinusoidal, square, or other periodicprofiles. For example, referring to FIG. 20, an embodiment oftime-modulated biasing 900 a signal 901 applied to electrodes to reduceexternal noise that is not at the modulation frequency. Modulating thesignal in time allows rejection of external noise that is not at themodulation frequency.

Embodiments include combining the differential layout strategy with themodulation strategy to achieve further improvements in signal-to-noiselevels.

Embodiments include employing a number of sensors having differentshapes, sizes, and spectral response (e.g., sensitivities to differentcolors). Embodiments include generating multi-level output signals.Embodiments include processing signals using suitable circuits andalgorithms to reconstruct information about the spectral and/or otherproperties of the light incident.

Advantages of the disclosed subject matter include transfer of accurateinformation about light intensity over longer distances than wouldotherwise be possible. Advantages include detection of lower levels oflight as a result. Advantages include sensing a wider range of possiblelight levels. Advantages include successful light intensitydetermination over a wider range of temperatures, an advantageespecially conferred when the dark reference is subtracted using thedifferential methods described herein.

Embodiments include a light sensor including a first electrode, a secondelectrode, and a third electrode. A light-absorbing semiconductor is inelectrical communication with each of the first, second, and thirdelectrodes. A light-obscuring material substantially attenuates theincidence of light onto the portion of light-absorbing semiconductorresiding between the second and the third electrodes, where anelectrical bias is applied between the second electrode and the firstand third electrodes and where the current flowing through the secondelectrode is related to the light incident on the sensor.

Embodiments include a light sensor including a first electrode, a secondelectrode, and a light-absorbing semiconductor in electricalcommunication with the electrodes wherein a time-varying electrical biasis applied between the first and second electrodes and wherein thecurrent flowing between the electrodes is filtered according to thetime-varying electrical bias profile, wherein the resultant component ofcurrent is related to the light incident on the sensor.

Embodiments include the above embodiments where the first, second, andthird electrodes consists of a material chosen from the list: gold,platinum, palladium, silver, magnesium, manganese, tungsten, titanium,titanium nitride, titanium dioxide, titanium oxynitride, aluminum,calcium, and lead.

Embodiments include the above embodiments where the light-absorbingsemiconductor includes materials taken from the list: PbS, PbSe, PbTe,SnS, SnSe, SnTe, CdS, CdSe, CdTe, Bi₂S₃, In₂S₃, In₂S₃, In₂Te₃, ZnS,ZnSe, ZnTe, Si, Ge, GaAs, polypyrolle, pentacene, polyphenylenevinylene,polyhexylthiophene, and phenyl-C61-butyric acid methyl ester.

Embodiments include the above embodiments where the bias voltages aregreater than about 0.1 V and less than about 10 V. Embodiments includethe above embodiments where the electrodes are spaced a distance betweenabout 1 μm and about 20 μm from one another.

Embodiments include the above embodiments where the distance between thelight-sensing region and active circuitry used in biasing and reading isgreater than about 1 cm and less than about 30 cm.

The capture of visual information regarding a scene, such as viaimaging, is desired in a range of areas of application. In cases, theoptical properties of the medium residing between the imaging system,and the scene of interest, may exhibit optical absorption, opticalscattering, or both. In cases, the optical absorption and/or opticalscattering may occur more strongly in a first spectral range compared toa second spectral range. In cases, the strongly-absorbing-or-scatteringfirst spectral range may include some or all of the visible spectralrange of approximately 470 nm to approximately 630 nm, and themore-weakly-absorbing-or-scattering second spectral range may includeportions of the infrared spanning a range of approximately 650 nm toapproximately 24 μm wavelengths.

In embodiments, image quality may be augmented by providing an imagesensor array having sensitivity to wavelengths longer than about a 650nm wavelength.

In embodiments, an imaging system may operate in two modes: a first modefor visible-wavelength imaging; and a second mode for infrared imaging.In embodiments, the first mode may employ a filter that substantiallyblocks the incidence of light of some infrared wavelengths onto theimage sensor.

Referring now to FIG. 21, an embodiment of a transmittance spectrum 1000of a filter that may be used in various imaging applications.Wavelengths in the visible spectral region 1001 are substantiallytransmitted, enabling visible-wavelength imaging. Wavelengths in theinfrared bands 1003 of approximately 750 nm to approximately 1450 nm,and also in a region 1007 beyond about 1600 nm, are substantiallyblocked, reducing the effect of images associated with ambient infraredlighting. Wavelengths in the infrared band 1005 of approximately 1450 nmto approximately 1600 nm are substantially transmitted, enablinginfrared-wavelength imaging when an active source having its principalspectral power within this band is turned on.

In embodiments, an imaging system may operate in two modes: a first modefor visible-wavelength imaging; and a second mode for infrared imaging.In embodiments, the system may employ an optical filter, which remainsin place in each of the two modes, that substantially blocks incidenceof light over a first infrared spectral band; and that substantiallypasses incidence of light over a second infrared spectral band. Inembodiments, the first infrared spectral band that is blocked may spanfrom about 700 nm to about 1450 nm. In embodiments, the second infraredspectral band that is substantially not blocked may begin at about 1450nm. In embodiments, the second infrared spectral band that issubstantially not blocked may end at about 1600 nm. In embodiments, inthe second mode for infrared imaging, active illuminating that includespower in the second infrared spectral band that is substantially notblocked may be employed. In embodiments, a substantiallyvisible-wavelength image may be acquired via image capture in the firstmode. In embodiments, a substantially actively-infrared-illuminatedimage may be acquired via image capture in the second mode. Inembodiments, a substantially actively-infrared-illuminated image may beacquired via image capture in the second mode aided by the subtractionof an image acquired during the first mode. In embodiments, aperiodic-in-time alternation between the first mode and second mode maybe employed. In embodiments, a periodic-in-time alternation betweenno-infrared-illumination, and active-infrared-illumination, may beemployed. In embodiments, a periodic-in-time alternation betweenreporting a substantially visible-wavelength image, and reporting asubstantially actively-illuminated-infrared image, may be employed. Inembodiments, a composite image may be generated which displays, inoverlaid fashion, information relating to the visible-wavelength imageand the infrared-wavelength image. In embodiments, a composite image maybe generated which uses a first visible-wavelength color, such as blue,to represent the visible-wavelength image; and uses a secondvisible-wavelength color, such as red, to represent theactively-illuminated infrared-wavelength image, in a manner that isoverlaid.

In image sensors, a nonzero, nonuniform, image may be present even inthe absence of illumination, (in the dark). If not accounted for, thedark images can lead to distortion and noise in the presentation ofilluminated images.

In embodiments, an image may be acquired that represents the signalpresent in the dark. In embodiments, an image may be presented at theoutput of an imaging system that represents the difference between anilluminated image and the dark image. In embodiments, the dark image maybe acquired by using electrical biasing to reduce the sensitivity of theimage sensor to light. In embodiments, an image sensor system may employa first time interval, with a first biasing scheme, to acquire asubstantially dark image; and a second time interval, with a secondbiasing scheme, to acquire a light image. In embodiments, the imagesensor system may store the substantially dark image in memory; and mayuse the stored substantially dark image in presenting an image thatrepresents the difference between a light image and a substantially darkimage. Embodiments include reducing distortion, and reducing noise,using the method.

In embodiments, a first image may be acquired that represents the signalpresent following reset; and a second image may be acquired thatrepresents the signal present following an integration time; and animage may be presented that represents the difference between the twoimages. In embodiments, memory may be employed to store at least one oftwo of the input images. In embodiments, the result difference image mayprovide temporal noise characteristics that are consistent withcorrelated double-sampling noise. In embodiments, an image may bepresented having equivalent temporal noise considerable less than thatimposed by sqrt(kTC) noise.

Embodiments include high-speed readout of a dark image; and of a lightimage; and high-speed access to memory and high-speed image processing;to present a dark-subtracted image to a user rapidly.

Embodiments include a camera system in which the interval between theuser indicating that an image is to be acquired; and in which theintegration period associated with the acquisition of the image; is lessthan about one second. Embodiments include a camera system that includesa memory element in between the image sensor and the processor.

Embodiments include a camera system in which the time in between shotsis less than about one second.

Embodiments include a camera system in which a first image is acquiredand stored in memory; and a second image is acquired; and a processor isused to generate an image that employs information from the first imageand the second image. Embodiments include generating an image with highdynamic range by combining information from the first image and thesecond image. Embodiments include a first image having a first focus;and a second image having a second focus; and generating an image fromthe first image and the second image having higher equivalent depth offocus.

Hotter objects generally emit higher spectral power density at shorterwavelengths than do colder objects. Information may thus be extractedregarding the relative temperatures of objects imaged in a scene basedon the ratios of power in a first band to the power in a second band.

In embodiments, an image sensor may comprise a first set of pixelsconfigured to sense light primarily within a first spectral band; and asecond set of pixels configured to sense light primarily within a secondspectral band. In embodiments, an inferred image may be reported thatcombines information from proximate pixels of the first and second sets.In embodiments, an inferred image may be reported that provides theratio of signals from proximate pixels of the first and second sets.

In embodiments, an image sensor may include a means of estimating objecttemperature; and may further include a means of acquiringvisible-wavelength images. In embodiments, image processing may be usedto false-color an image representing estimated relative objecttemperature atop a visible-wavelength image.

In embodiments, the image sensor may include at least one pixel havinglinear dimensions less than approximately 2 μm×2 μm.

In embodiments, the image sensor may include a first layer providingsensing in a first spectral band; and a second layer providing sensingin a second spectral band.

In embodiments, visible images can be used to present a familiarrepresentation to users of a scene; and infrared images can provideadded information, such as regarding temperature, or pigment, or enablepenetration through scattering and/or visible-absorbing media such asfog, haze, smoke, or fabrics.

In cases, it may be desired to acquire both visible and infrared imagesusing a single image sensor. In cases, registration among visible andinfrared images is thus rendered substantially straightforward.

In embodiments, an image sensor may employ a single class oflight-absorbing light-sensing material; and may employ a patterned layerabove it that is responsible for spectrally-selective transmission oflight through it, also known as a filter. In embodiments, thelight-absorbing light-sensing material may providehigh-quantum-efficiency light sensing over both the visible and at leasta portion of the infrared spectral regions. In embodiments, thepatterned layer may enable both visible-wavelength pixel regions, andalso infrared-wavelength pixel regions, on a single image sensorcircuit.

In embodiments, an image sensor may employ two classes oflight-absorbing light-sensing materials: a first material configured toabsorb and sense a first range of wavelengths; and a second materialconfigured to absorb and sense a second range of wavelengths. The firstand second ranges may be at least partially overlapping, or they may notbe overlapping.

In embodiments, two classes of light-absorbing light-sensing materialsmay be placed in different regions of the image sensor. In embodiments,lithography and etching may be employed to define which regions arecovered using which light-absorbing light-sensing materials. Inembodiments, ink jet printing may be employed to define which regionsare covered using which light-absorbing light-sensing materials.

In embodiments, two classes of light-absorbing light-sensing materialsmay be stacked vertically atop one another. In embodiments, a bottomlayer may sense both infrared and visible light; and a top layer maysense visible light principally.

In embodiments, an optically-sensitive device may include: a firstelectrode; a first light-absorbing light-sensing material; a secondlight-absorbing light-sensing material; and a second electrode. Inembodiments, a first electrical bias may be provided between the firstand second electrodes such that photocarriers are efficiently collectedprimarily from the first light-absorbing light-sensing material. Inembodiments, a second electrical bias may be provided between the firstand second electrodes such that photocarriers are efficiently collectedprimarily from the second light-absorbing light-sensing material. Inembodiments, the first electrical bias may result in sensitivityprimarily to a first wavelength of light. In embodiments, the secondelectrical bias may result in sensitivity primarily to a secondwavelength of light. In embodiments, the first wavelength of light maybe infrared; and the second wavelength of light may be visible. Inembodiments, a first set of pixels may be provided with the first bias;and a second set of pixels may be provided with the second bias;ensuring that the first set of pixels responds primarily to a firstwavelength of light, and the second set of pixels responds primarily toa second wavelength of light.

In embodiments, a first electrical bias may be provided during a firstperiod of time; and a second electrical bias may be provided during asecond period of time; such that the image acquired during the firstperiod of time provides information primarily regarding a firstwavelength of light; and the image acquired during the second period oftime provides information primarily regarding a second wavelength oflight. In embodiments, information acquired during the two periods oftime may be combined into a single image. In embodiments, false-colormay be used to represent, in a single reported image, informationacquired during each of the two periods of time.

In embodiments, a focal plane array may consist of a substantiallylaterally-spatially uniform film having a substantiallylaterally-uniform spectral response at a given bias; and having aspectral response that depends on the bias. In embodiments, a spatiallynonuniform bias may be applied, for example, different pixel regions maybias the film differently. In embodiments, under a givenspatially-dependent biasing configuration, different pixels may providedifferent spectral responses. In embodiments, a first class of pixelsmay be responsive principally to visible wavelengths of light, while asecond class of pixels may be responsive principally to infraredwavelengths of light. In embodiments, a first class of pixels may beresponsive principally to one visible-wavelength color, such as blue;and a second class of pixels may be responsive principally to adistinctive visible-wavelength color, such as green; and a third classof pixels may be responsive principally to a distinctivevisible-wavelength color, such as red.

In embodiments, an image sensor may comprise a readout integratedcircuit, at least one pixel electrode of a first class, at least onepixel electrode of a second class, a first layer of optically sensitivematerial, and a second layer of optically sensitive material. Inembodiments, the image sensor may employ application of a first bias forthe first pixel electrode class; and of a second bias to the secondpixel electrode class.

In embodiments, those pixel regions corresponding to the first pixelelectrode class may exhibit a first spectral response; and of the secondpixel electrode class may exhibit a second spectral response; where thefirst and second spectral responses are significantly different. Inembodiments, the first spectral response may be substantially limited tothe visible-wavelength region. In embodiments, the second spectralresponse may be substantially limited to the visible-wavelength region.In embodiments, the second spectral response may include both portionsof the visible and portions of the infrared spectral regions.

In embodiments, it may be desired to fabricate an image sensor havinghigh quantum efficiency combined with low dark current.

In embodiments, a device may consist of: a first electrode; a firstselective spacer; a light-absorbing material; a second selective spacer;and a second electrode.

In embodiments, the first electrode may be used to extract electrons. Inembodiments, the first selective spacer may be used to facilitate theextraction of electrons but block the injection of holes. Inembodiments, the first selective spacer may be an electron-transportlayer. In embodiments, the light-absorbing material may includesemiconductor nanoparticles. In embodiments, the second selective spacermay be used to facilitate the extraction of holes but block theinjection of electrons. In embodiments, the second selective spacer maybe a hole-transport layer.

In embodiments, only a first selective spacer may be employed. Inembodiments, the first selective spacer may be chosen from the list:TiO₂, ZnO, ZnS. In embodiments, the second selective spacer may be NiO.In embodiments, the first and second electrode may be made using thesame material. In embodiments, the first electrode may be chosen fromthe list: TiN, W, Al, Cu. In embodiments, the second electrode may bechosen from the list: ZnO, Al:ZnO, ITO, MoO₃, Pedot, Pedot:PSS.

In embodiments, it may be desired to implement an image sensor in whichthe light-sensing element can be configured during a first interval toaccumulate photocarriers; and during a second interval to transferphotocarriers to another node in a circuit.

Embodiments include a device comprising: a first electrode; a lightsensing material; a blocking layer; and a second electrode.

Embodiments include electrically biasing the device during a firstinterval, known as the integration period, such that photocarriers aretransported towards the first blocking layer; and where photocarriersare stored near the interface with the blocking layer during theintegration period.

Embodiments include electrically biasing the device during a secondinterval, known as the transfer period, such that the storedphotocarriers are extracted during the transfer period into another nodein a circuit.

Embodiments include a first electrode chosen from the list: TiN, W, Al,Cu. In embodiments, the second electrode may be chosen from the list:ZnO, Al:ZnO, ITO, MoO₃, Pedot, Pedot:PSS. In embodiments, the blockinglayer be chosen from the list: HfO₂, Al₂O₃, NiO, TiO₂, ZnO.

In embodiments, the bias polarity during the integration period may beopposite to that during the transfer period. In embodiments, the biasduring the integration period may be of the same polarity as that duringthe transfer period. In embodiments, the amplitude of the bias duringthe transfer period may be greater than that during the integrationperiod.

Embodiments include a light sensor in which an optically sensitivematerial functions as the gate of a silicon transistor. Embodimentsinclude devices comprising: a gate electrode coupled to a transistor; anoptically sensitive material; a second electrode. Embodiments includethe accumulation of photoelectrons at the interface between the gateelectrode and the optically sensitive material. Embodiments include theaccumulation of photoelectrons causing the accumulation of holes withinthe channel of the transistor. Embodiments include a change in the flowof current in the transistor as a result of a change in photoelectronsas a result of illumination. Embodiments include a change in currentflow in the transistor greater than 1000 electrons/s for everyelectron/s of change in the photocurrent flow in the optically sensitivelayer. Embodiments include a saturation behavior in which the transistorcurrent versus photons impinged transfer curve has a sublineardependence on photon fluence, leading to compression and enhanceddynamic range. Embodiments include resetting the charge in the opticallysensitive layer by applying a bias to a node on the transistor thatresults in current flow through the gate during the reset period.

Embodiments include combinations of the above image sensors, camerasystems, fabrication methods, algorithms, and computing devices, inwhich at least one image sensor is capable of operating in globalelectronic shutter mode.

In embodiments, at least two image sensors, or image sensor regions, mayeach operate in global shutter mode, and may provide substantiallysynchronous acquisition of images of distinct wavelengths, or fromdifferent angles, or employing different structured light.

Embodiments include implementing correlated double-sampling in theanalog domain. Embodiments include so doing using circuitry containedwithin each pixel. FIG. 22 shows an example schematic diagram of acircuit 1100 that may be employed within each pixel to reduce noisepower. In embodiments, a first capacitor 1101 (C₁) and a secondcapacitor 1103 (C₂) are employed in combination as shown. Inembodiments, the noise power is reduced according to the ratio C₂/C₁.

FIG. 23 shows an example schematic diagram of a circuit 1200 of aphotoGate/pinned-diode storage that may be implemented in silicon. Inembodiments, the photoGate/pinned-diode storage in silicon isimplemented as shown. In embodiments, the storage pinned diode is fullydepleted during reset. In embodiments, C₁ (corresponding to the lightsensor's capacitance, such as quantum dot film in embodiments) sees aconstant bias.

In embodiments, light sensing may be enabled through the use of a lightsensing material that is integrated with, and read using, a readoutintegrated circuit. Example embodiments of same are included in U.S.Provisional Application No. 61/352,409, entitled, “Stable, SensitivePhotodetectors and Image Sensors Made Therefrom Including Circuits forEnhanced Image Performance,” and U.S. Provisional Application No.61/352,410, entitled, “Stable, Sensitive Photodetectors and ImageSensors Made Therefrom Including Processes and Materials for EnhancedImage Performance,” both filed Jun. 8, 2010, which are herebyincorporated by reference in their entirety.

In embodiments, a method of gesture recognition is provided where themethod includes acquiring a stream, in time, of at least two images fromeach of at least one camera module; acquiring a stream, in time, of atleast two signals from each of at least one light sensor; and conveyingthe at least two images and the at least two signals to a processor, theprocessor being configured to generate an estimate of a gesture'smeaning, and timing, based on a combination of the at least two imagesand the at least two signals.

In embodiments, the at least one light sensor includes a light-absorbingmaterial having an absorbance, across the visible wavelength region ofabout 450 nm to about 650 nm, of less than about 30%.

In embodiments, the light-absorbing material includes PBDTT-DPP, thenear-infrared light-sensitive polymerpoly(2,60-4,8-bis(5-ethylhexylthienyl)benzo-[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione).

In embodiments, the at least one light sensor includes a light-sensingmaterial capable of sensing infrared light.

In embodiments, the method includes modulating a light source using atleast one code selected from spatial codes and temporal codes.

In embodiments, the light source has an emission wavelength in the rangeof about 900 nm to about 1000 nm.

In one embodiment, a camera system includes a central imaging arrayregion, at least one light-sensing region outside of the central imagingarray region, a first mode, referred to as imaging mode, and a secondmode, referred to as sensing mode. The electrical power consumed in thesecond mode is at least 10 times lower than the electrical powerconsumed in the first mode.

In embodiments, the at least one light sensor includes a light-sensingmaterial capable of sensing infrared light.

In embodiments, light impinging on the light-sensing material is to bemodulated.

In embodiments, a portion of light impinging on the light-sensingmaterial is to be generated using a light emitter device having anemission wavelength in the range of about 800 nm to about 1000 nm.

In embodiments, the central imaging array includes at least sixmegapixels.

In embodiments, the central imaging array comprises pixels less thanapproximately 2 μm in width and approximately 2 μm in height.

In one embodiment, an image sensor circuit includes a central imagingarray region having a first field of view; and at least onelight-sensing region outside of the central imaging array region havinga second field of view. The second field of view is less than half,measured in angle, the field of view of the first field of view.

In one embodiment, an integrated circuit includes a substrate, an imagesensing array region occupying a first region of said semiconductorsubstrate and including a plurality of optically sensitive pixelregions, a pixel circuit for each pixel region, each pixel circuitcomprising a charge store and a read-out circuit, and a light-sensitiveregion outside of the image sensing array region. The image sensingarray region having a first field of view and the light-sensitive regionhaving a second field of view; the angle of the second field of view isless than half of the angle of the first field of view.

In embodiments, at least one of the image sensing array and thelight-sensitive region outside of the image sensing array regionincludes a light-sensing material capable of sensing infrared light.

In embodiments, light impinging on at least one of the image sensingarray and the light-sensitive region outside of the image sensing arrayregion is to be modulated.

In embodiments, a portion of light impinging on at least one of theimage sensing array and the light-sensitive region outside of the imagesensing array region is to be generated using a light emitter devicehaving an emission wavelength in the range of about 800 nm to about 1000nm.

In embodiments, the image sensing array includes at least sixmegapixels.

In embodiments, the image sensing array comprises pixels less thanapproximately 2 μm in width and approximately 2 μm in height.

In one embodiment, an image sensor includes a central imaging arrayregion to provide pixelated sensing of an image, in communication with aperipheral region that includes circuitry to provide biasing, readout,analog-to-digital conversion, and signal conditioning to the pixelatedlight sensing region. An optically sensitive material overlies theperipheral region.

In embodiments, the at least one light sensor includes a light-sensingmaterial capable of sensing infrared light.

In embodiments, light impinging on the light-sensing material is to bemodulated.

In embodiments, a portion of light impinging on the light-sensingmaterial is to be generated using a light emitter device having anemission wavelength in the range of about 800 nm to about 1000 nm.

In embodiments, the central imaging array includes at least sixmegapixels.

In embodiments, the central imaging array comprises pixels less thanapproximately 2 μm in width and approximately 2 μm in height.

In embodiments, the optically sensitive material is chosen to include atleast one material from a list, the list including silicon, colloidalquantum dot film, and a semiconducting polymer.

In embodiments, the optically sensitive material is fabricated on afirst substrate, and is subsequently incorporated onto the centralimaging array region.

In one embodiment, a mobile computing device includes a semiconductorsubstrate, an image sensor comprising pixel circuitry formed on thesemiconductor substrate and an image sensing region, a photosensorcomprising read-out circuitry formed on the semiconductor substrate anda light sensitive region, circuitry configured to read an image from theimage sensor, a processor configured to process a signal read from thephotosensor proportional to an optical signal sensed by the photosensor,and control circuitry configured in at least one mode to provide powerto read the photosensor without providing power to read-out the imagesensor such that power consumption is reduced compared to a mode wherethe power is provided to operate the image sensor.

In various ones of the embodiments discussed herein, additionalembodiments include the semiconductor substrate comprising a die ofsilicon. In embodiments, the semiconductor substrate comprises a singledie of silicon. In embodiments, the semiconductor substrate comprises anintegrated circuit. In embodiments, each pixel circuit comprisescircuitry formed on the semiconductor substrate. In embodiments, theread-out circuit for the light-sensitive region comprises circuitryformed on the semiconductor substrate. In embodiments, the image sensingregion and the light-sensitive region are formed on the semiconductorsubstrate. In embodiments, the image sensing region and thelight-sensitive region are formed on the single die of silicon. Inembodiments, the image sensing region and the light-sensitive regioneach comprise a layer of photosensitive material on the semiconductorsubstrate. In embodiments, the control circuitry is formed on thesemiconductor substrate. In embodiments, the control circuitry is formedon the semiconductor substrate.

In various ones of the embodiments discussed herein, additionalembodiments include the electrical power consumed by the controlcircuitry and the photosensor during the second mode is at least 100times lower than electrical power consumed by the control circuitry andthe image sensor during the first mode. In embodiments, electrical powerconsumed to operate the photosensor is at least ten (10) times lowerthan electrical power consumed to operate the image sensor. Inembodiments, electrical power consumed to operate the photosensor is atleast fifty (50) times lower than electrical power consumed to operatethe image sensor. In embodiments, electrical power consumed to operatethe photosensor is at least one hundred (100) times lower thanelectrical power consumed to operate the image sensor. In embodiments,electrical power consumed to operate the photosensor is less than about1 milliwatt (mW). In embodiments, electrical power consumed to operatethe photosensor is less than about 10 milliwatt (mW).

In various ones of the embodiments discussed herein, additionalembodiments include the photosensor is configured to sense light in atleast one mode of operation without providing power to the image sensor.In embodiments, a read-out circuit for the photosensor operatesindependently from the power provided to the semiconductor substrate. Inembodiments, a read-out circuit for the photosensor separate from thesemiconductor substrate is configured to read-out a signal from thephotosensor in at least one mode of operation without power beingprovided to the semiconductor substrate. In embodiments, a read-outcircuit for the photosensor is separate from the semiconductor substratethat is configured to read-out a signal from the photosensor in at leastone mode of operation without power being provided to the image sensor.In embodiments, a power management unit is provided for the mobiledevice, the power management unit is separate from the semiconductorsubstrate and is configured to monitor current from the, for example,photosensor and/or light sensitive region.

In various ones of the embodiments discussed herein, additionalembodiments include that the photosensor is passive. In embodiments, theimage sensor is active. In embodiments, the semiconductor substrateincludes on-chip power routed to the image sensor. In embodiments, theon-chip power on the semiconductor substrate is not routed to thephotosensor. In embodiments, the photosensor is operated independentlyof the on-chip power on the semiconductor substrate.

In various ones of the embodiments discussed herein, additionalembodiments include the image sensing region having an area that is atleast 10 times greater than an area of the photosensor. In embodiments,the image sensing region has an area greater than 40 mm². Inembodiments, the photosensor has an area less than 4 mm². Inembodiments, the image sensing region comprises a plurality of pixelregions, with each pixel region is less than about 2 micron (μm) inwidth and less than about 2 micron (μm) in height. In embodiments, theimage sensing region comprises a plurality of pixel regions, with eachpixel region has an area less than about 4 micron squared (μm²). Inembodiments, the image sensing region comprises more than 2 millionpixel regions. In embodiments, the photosensor has an area ofphotosensitive material coupled to a where the photosensitive region isgreater than 1 to 100 micrometers squared (μm²). In embodiments, thephotosensor comprises binned pixel regions having a total binned area ofat least 100 microns squared (μm²).

In various ones of the embodiments discussed herein, additionalembodiments include the image sensing region being in a center region ofan image circle. In embodiments, the photosensor is in a peripheralregion of an image circle further comprising optics configured to focuslight onto the image sensing region on the semiconductor substrate, theimage sensing region being positioned substantially near the center ofthe image circle. In embodiments, the photosensor is positioned in aperipheral region of the image circle. In embodiments, the photosensoris peripheral to the image sensing region. In embodiments, thephotosensor is positioned in a peripheral segment of the image circle.In embodiments, the photosensor has a non-rectangular shape.

In various ones of the embodiments discussed herein, additionalembodiments include a second photosensor, the second photosensor beingpositioned in a peripheral region of the image circle. In embodiments,the first and second photosensors are positioned on opposite sides ofthe image sensing region. In embodiments, the image sensing region ispositioned substantially at the center of the image circle such thatthere are four peripheral regions around the image sensing region. Inembodiments, each peripheral region includes at least one photosensor.In embodiments, is the image sensor region is configured to sensevisible light, and at least one of the photosensors is configured tosense infrared light

In various ones of the embodiments discussed herein, additionalembodiments include the image sensing region and light sensing regioncomprise the same photosensitive material. In embodiments, the firstphotosensor and second photosensor comprise the same photosensitivematerial. In embodiments, a filter is positioned to filter lightincident on the image sensor region within a predetermined range. Inembodiments, an infrared (IR) filter configured to block infrared lightimpinging on the image sensing region, and to pass infrared lightimpinging on the photosensor(s). In embodiments, the light incident onthe photosensor is selectively filtered relative to the image sensingregion. In embodiments, the image sensing region comprises a firstphotosensitive material and the light sensing region comprises a secondphotosensitive material. In embodiments, the first photosensitivematerial has a different sensitivity to wavelength of light than thesecond photosensitive material. In embodiments, the first photosensitivematerial has a higher sensitivity to visible light than the secondphotosensitive material. In embodiments, the second photosensitivematerial has a higher sensitivity to infrared (IR) light than the firstphotosensitive material. In embodiments, the photosensor comprises afirst photosensitive material and the second photosensor comprises asecond photosensitive material. In embodiments, the first photosensitivematerial has a different sensitivity to wavelength of light than thesecond photosensitive material. In embodiments, the first photosensitivematerial has a higher sensitivity to infrared (IR) light than the secondphotosensitive material. In embodiments, the second photosensitivematerial has a higher sensitivity to near infrared (NIR) light than thefirst photosensitive material. In embodiments, the first photosensitivematerial comprises a layer of nanocrystal material. In embodiments, thephotosensitive material of the image sensing region comprises silicon;and the photosensitive material of the photosensor comprises a layernanocrystal photosensitive material.

In various ones of the embodiments discussed herein, additionalembodiments include optics configured to focus light on an image circlecovering both the image sensing region and the photosensor. Inembodiments, the image sensing region and the photosensor are positionedin the focal plane of the optics. In embodiments, the image sensingregion is in a central region of image circle and the photosensor is ina peripheral region of the image circle.

In various ones of the embodiments discussed herein, additionalembodiments include the semiconductor substrate having circuitry in theperipheral region wherein the light sensing region is formed over atleast some of the circuitry. In embodiments, the circuitry (e.g., in theperipheral region) comprises circuitry formed on the semiconductorsubstrate outside the area of the image sensing region. In embodiments,at least some of the circuitry is positioned below the photosensor.

In various ones of the embodiments discussed herein, additionalembodiments include the read-out circuit comprising circuitry below theimage sensing region. In embodiments, the control circuitry and or theread-out circuit are formed on the substrate (e.g., where the substratemay be a semiconductor substrate).

In various ones of the embodiments discussed herein, additionalembodiments include providing a bias across the photosensitive materialof the image sensing region of approximately 1 to 4 V. In embodiments,the circuitry provides a bias across the photosensitive material of thephotosensor of approximately 1V to 4 V.

In embodiments, the bias to the photosensitive material of the imagesensing region can be selectively turned off independently of the biasacross the photosensitive material of the photosensor. In embodiments,the photosensor comprises a first electrode and a second electrode, anda bias provided to the first electrode is independent of a bias appliedto the second electrode.

In various ones of the embodiments discussed herein, additionalembodiments include the read-out circuit for the photosensor comprisescircuitry being below the image sensing region. In embodiments, theread-out circuit for the photosensor comprises off-chip circuitryseparate from the semiconductor substrate. In embodiments, the read-outcircuit for the photosensor comprises a current monitor. In embodiments,the read-out circuit for the photosensor comprises a counter. Inembodiments, the read-out circuit for the photosensor comprises a chargepump. In embodiments, the read-out circuit for the photosensor comprisescircuitry formed on the semiconductor substrate. In embodiments, theread-out circuit for the photosensor is configured to generate, forexample, a signal, a digital number, or a counter signal indicative oflight incident on, for example, the photosensor or the light sensingmaterial.

In various ones of the embodiments discussed herein, additionalembodiments include the semiconductor substrate including power routedto a photosensor separately from power routed to the image sensor suchthat power can be provided to the photosensor when the power to theimage sensor is turned off.

In various ones of the embodiments discussed herein, additionalembodiments include the image sensor comprising a back side illumination(BSI) silicon image sensor. In embodiments, the photosensor comprisespixel regions coupled to a reset gate of a pixel circuit for currentcollection. In embodiments, the, for example, image sensor orphotosensor comprises silicon photodiodes.

In various ones of the embodiments discussed herein, additionalembodiments include the image sensing region being configured to have afirst field of view and the photosensor being configured to have asecond field of view at a different angle than the first field of view.In embodiments, the first photosensor has a first field of view andsecond photosensor has a second field of view at a different angle thanthe first field of view. In embodiments, each photosensor has a field ofview at a different angle than each other photosensor. In embodiments,the photosensor has a first field of view, and the second photosensorhas a second field-of-view.

In various ones of the embodiments discussed herein, additionalembodiments include further comprising a light source for illuminating ascene. In embodiments, the light source is modulated. In embodiments,the photosensor is configured to sense modulated light reflected fromthe scene. In embodiments, a processor is configured to process a signalfrom the photosensor indicative of the modulated light reflected fromthe scene for gesture recognition.

In various ones of the embodiments discussed herein, additionalembodiments include a processor configured to process a signal from thephotosensor indicative of the modulated light reflected from the scenefor gesture recognition. In embodiments, a processor is configured toprocess a signal from the photosensor from a first field of viewindicative of the modulated light reflected from the scene for gesturerecognition. In embodiments, a processor is configured to process asignal from each of the photosensors for gesture recognition. Inembodiments, the signal from each photosensor is indicative of themodulated light reflected from the scene for a different field of thanthe other photosensors.

The disclosed subject matter also describes means of sensing lightlevels, and/or sensing gestures, using an image sensor. In embodiments,the disclosed subject matter includes devices and methods that minimizeor reduce the consumption of electrical power. In embodiments, thedisclosed subject matter includes devices and methods that employ animage sensor used to capture still pictures and videos, at least one ofwhich is often provided in a mobile device, and provides improved meansof doing so.

FIG. 24 shows a top-view schematic of an image sensor in which aphotosensitive material, also known as an optically sensitive layer, isprovided on top of an integrated circuit, such as a CMOS integratedcircuit.

In FIG. 24, the top/transparent square represents an electrode to whicha bias labeled V_(film) is applied. Electrical current (not explicitlyshown) is passed to the same node as indicated with V_(film). Theexample case depicted in FIG. 24 indicates a single, substantiallytransparent, conductive electrode that overlies the optically sensitivelayer. It provides an electrical bias between the top of the opticallysensitive layer, and pixel electrodes underlying the optically sensitivelayer. The underlying pixel electrodes are typically in electricalcommunication with the integrated circuit mentioned above. Under theapplication of the electrical bias provided via the potential differencebetween Vfilm and the potential of each pixel electrode, a photocurrentflows that is related to the illumination of each pixel region definedby each pixel electrode underlying each region of optically sensitivematerial. The charge collected in each pixel is then read by the readoutintegrated circuit and can be used to provide a data stream offeringstill images, or video, including conveying the data streams to otherportions of the mobile device.

In the example of FIG. 24, a single top electrode is connected to apower supply that provides the correct electric field vertically acrossthe optically sensitive layer. The current flowing into the topelectrode is related to the sum of the photocurrents flowing in thetotality of all pixel electrodes in the array beneath.

In the example embodiment of FIG. 24, the electrical current at theV_(film) electrode of FIG. 24 may be measured. In embodiments, thecurrent integrated over an integration time may be converted into avoltage by integrating the current, over an integration period, into adevice having a known capacitance, for example, a known charge store. Inexample embodiments, the current, or the voltage, may be measured usingan added circuit. For example, an analog-to-digital converter may beemployed to estimate the average current that flowed over theintegration period. In this example, a digital code may be reported thatis related, in a known fashion, to the ambient light level.

Notably, significant portions of the readout integrated circuit do notrequire power during this operation. In an example embodiment, bias maybe applied to each pixel electrode in order to ensure the neededelectrical biasing between the bottom pixel electrodes and the commontop contact. However, the analog-to-digital converter used on chip forhigh-data-rate readout of each signal in each pixel may be powered down,or may operate at lower power. Current monitoring may be applied using acircuit such as a current integrator, a current multiplier, a directcurrent to digital converter, or other implementations.

An example means of resetting the pixel electrodes is depicted in FIG.28, where an example of a pixel readout circuit is included in thedashed box. In this figure, the pixel readout is a 3T architecturecomposed of a reset transistor, a source follower transistor, and aselect transistor, but alternative pixel readout architectures may beused instead. In this example, the reset transistor of each pixel of anarbitrary area of pixels is connected to a single line labeled “reset”which is monitored by a current sensing circuit, for example, a seriesresistor and a voltmeter. In this example embodiment, the multiplebottom contacts of the photosensitive layer may be electrically shortedto a second power supply, which may be the pixel power supply, through aper pixel switch, which may be the pixel reset gate as shown in FIG. 28.In this example embodiment, the entire current from the entire imagingarray may be read, and this may be done while some or all of the readoutintegrated circuit is powered down. When ambient light changes aredetected through the current monitor circuits, an external controllermay be employed to power up the readout chip in order to enable still orvideo capture as shown by signals in FIG. 29. As an example, if thepixel array area is composed by 10,000 pixels and each pixel provides a10 pA photo-current at a specific lighting condition, and 100 pA at adifferent, brighter lighting condition, the current monitor will bedesigned so that it can detect a difference between 10,000*10 pA=0.1 μAand 10,000*100 pA=1 μA.

FIG. 30 depicts a typical open loop system where a controller decideswhen to power up the readout chip, the device display, or otherfunctions as a function of the signal provided by the current sensingcircuit. In this example, the image sensor is kept in ultra-low powermode with all internal circuits powered down with the exception of thepixel array reset transistor drivers, the current sensing circuit, andthe V_(film) bias generator, which allows the photo-sensitive materialgenerated current to flow through the current sensing circuit.

Referring now to FIG. 25, a top-view schematic of an image sensor isshown that is analogous to FIG. 24; except that, distinct from FIG. 24,there are now defined (in this example embodiment) four separate regionsof top transparent electrical contact. The respective voltages providedto each region are labeled V_(film1), V_(film2), V_(film3), andV_(film4). Photocurrents, generally proportional to light absorbedwithin each distinct region of an optically sensitive layer underlyingthe rectangular regions labeled with V_(film1), V_(film2), V_(film3),and V_(film4), now become available for measurement. Operation of thecircuits with reference to FIG. 28 and FIG. 29 remain analogous to themeans described in the context of FIG. 24. However, now there exists alarger number (in this example, four) of substantially independentregions. These regions can be associated with substantially independentcurrent monitoring devices. Thus, sensing of nonuniform illuminationacross the totality of the array can be provided. For example, atime-varying and spatially-varying signal from the four quadrants couldbe interpreted as a “wake-up” gesture, which would signal to controldevices that power should be returned to portions of the mobile device.

The concept of FIG. 25 can be further extended to dividing the V_(film)top contact in n*m areas as shown in FIG. 26 for a higher spatialresolution. In some embodiments, n may be equal to m. Regions ofdifference sizes and areas and shapes can be provided by using distinctshapes as depicted in FIG. 27. In the example embodiment of FIG. 27,smaller corner regions may be provided for sensing gesture in space andtime; while the center of the array may be used for maximum-sensitivity(in view of its larger area hence larger photocurrent) detection of theaverage ambient illumination conditions.

In embodiments, instead of providing an optically sensitive layerutilizing some non-standard material not traditionally employed in CMOSintegrated circuits, the concepts described herein can be deployed inCMOS imagers. In an example embodiment, the current monitor may beplaced on the pixel reset line of FIG. 28, where the pixel reset linemay be common to a cluster of pixels with arbitrary size and shape. Aspreviously described, the image sensor could be substantially poweredoff, and some or all pixels may be electrically connected to the resetlines through the reset transistors. In embodiments, the integratedcircuit may remain in this power down, or low-power, state, until acertain amount of current or current variation is detected by thesensing circuit. At this time, a controller may wake this chip, portionsof this chip, or wake up other devices within a mobile device.

In the case of multiple sensing regions some basic gesture recognition,such as left-to-right or right-to-left hand gesture, can be performedand used to control the device operation while providing very low powerconsumption.

In various embodiments, an image sensor is disclosed. In embodiments,the image sensor includes a read-out integrated circuit, a plurality ofpixel electrodes, an optically sensitive layer, and a top electricalcontact. In embodiments, in a first low-power mode, electrical currentpassing through the top electrical contact is to be sensed, andindependent currents passing through the plurality of pixel electrodesare not to be sensed independently. In embodiments, in a secondhigh-resolution mode, independent currents passing through the pluralityof pixel electrodes are to be sensed independently.

In various embodiments, an image sensor is disclosed. In embodiments,the image sensor includes a read-out integrated circuit, a plurality ofpixel electrodes, an optically sensitive layer, and at least twoindependent top electrical contacts. In embodiments, in a firstlow-power mode, electrical current passing through the first topelectrical contact is to be sensed, electrical current passing throughthe at least second top electrical contact is to be sensed, andindependent currents passing through the plurality of pixel electrodesare not to be sensed independently. In embodiments, in a secondhigh-resolution mode, independent currents passing through the pluralityof pixel electrodes are to be sensed independently.

In various embodiments, a method of regulating power distribution in amobile device is disclosed. In embodiments, the method includes sensing,in a low-power mode, information regarding illumination of a sensor inthe mobile device by measuring a photocurrent through at least oneelectrode disposed on or above an image sensor integrated circuit,providing the sensed information to a controller circuit, determining,using the controller circuit, a rate of change in at least one of spaceand time of the conditions illuminating the sensor, and providing anoutput from the controller circuit to implement a power-up of acomponent within the mobile device.

The various illustrations of the methods and apparatuses provided hereinare intended to provide a general understanding of the structure ofvarious embodiments and are not intended to provide a completedescription of all the elements and features of the apparatuses andmethods that might make use of the structures, features, and materialsdescribed herein.

A person of ordinary skill in the art will appreciate that, for this andother apparatuses and methods disclosed herein, thesections/portions/circuits/devices and activities forming part ofvarious apparatuses and methods may, in certain cases, be implemented ina differing order, as well as repeated, executed simultaneously, orsubstituted one for another. Further, the outlined apparatuses, acts,and operations are only provided as examples, and some of theapparatuses, acts, and operations may be optional, combined into fewerapparatuses, acts, and operations, or expanded into additionalapparatuses, acts, and operations without detracting from the essence ofthe disclosed embodiments.

The present disclosure is therefore not to be limited in terms of theparticular embodiments described in this application, which are intendedas illustrations of various aspects. Many modifications and variationscan be made, as will be apparent to a person of ordinary skill in theart upon reading and understanding the disclosure. Functionallyequivalent methods and apparatuses within the scope of the disclosure,in addition to those enumerated herein, will be apparent to a person ofordinary skill in the art from the foregoing descriptions. Portions andfeatures of some embodiments may be included in, or substituted for,those of others. Many other embodiments will be apparent to those ofordinary skill in the art upon reading and understanding the descriptionprovided herein. Such modifications and variations are intended to fallwithin a scope of the appended claims. The present disclosure is to belimited only by the terms of the appended claims, along with the fullscope of equivalents to which such claims are entitled. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only and is not intended to belimiting.

In addition, in the foregoing Detailed Description, it may be seen thatvarious features are grouped together in a single embodiment for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as limiting the claims. Thus, the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separate embodiment.

Consequently, the various illustrations of the procedures andapparatuses are intended to provide a general understanding of thestructure of various embodiments and are not intended to provide acomplete description of all the elements and features of the apparatusesand methods that might make use of the structures, features, andmaterials described herein. Based upon a reading and understanding ofthe disclosed subject matter provided herein, a person of ordinary skillin the art can readily envision other combinations and permutations ofthe various embodiments. The additional combinations and permutationsare all within a scope of the present invention.

The Abstract of the disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. The Abstractis submitted with the understanding that it will not be used tointerpret or limit the claims. In addition, in the foregoing DetailedDescription, it may be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as limiting theclaims. Thus, the following claims are hereby incorporated into theDetailed Description, with each claim standing on its own as a separateembodiment.

What is claimed is:
 1. A method of regulating power distribution in amobile device, the method comprising: sensing, in a low-power mode,information regarding illumination of a sensor in the mobile device bymeasuring a photocurrent through at least one electrode disposed on orabove an image sensor integrated circuit; providing the sensedinformation to a controller circuit; determining, using the controllercircuit, a rate of change in at least one of space and time of theconditions illuminating the sensor; and providing an output from thecontroller circuit to implement a power-up of a component within themobile device.